388
Documenta Praehistorica XLIX (2022)
Introduction
How was pottery fired in the Early Iron Age in what
is today western Slovenia? Can we assume the use
of kilns despite their absence? On the territory of
present-day Italy, two-part updraft kilns with a sepa-
rate fireplace and firing chamber were known in this
period, while on the territory of Slovenia they ap-
pear no sooner than in the Late Iron Age. We assume
that the preservation of such structures in the dis-
cussed areas depends on various factors, so we will
show the possible reasons for the poor preservation
of these based on the results of experimental archa-
eology. Through macro- and microscopic analyses of
Pottery firing in the Early Iron Age
in western Slovenia
Manca Vinazza1, Matej Dolenec2
manca.vinazza@ff.uni-lj.si< matej.dolenec@ntf.uni-lj.si
1 University of Ljubljana, Faculty of Arts, Department of Archaeology, SI 
2 University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Geology, SI
ABSTRACT – The article discusses the possible use of kilns for the firing of pottery in western Slove-
nia during the Early Iron Age. In the absence of archaeologically attested kilns, their use in this area
is studied based on indirect factors, i.e. the analysis of the vessel firing technique, and with the help
of experiments from the field of experimental archaeology. The article strives to determine the rea-
sons for the poor state of preservation of the kilns in the area in question. Samples from archaeo-
logical experiments and archaeological pottery were subjected to AMS measurements, petrographic
and mineralogical analyses (X-ray diffraction), which revealed the importance of considering the
soaking time as a criterion for observing the firing processes and use of single-chamber kilns for the
firing of pottery, even if they have not yet been discovered. 
IZVLE∞EK – V ≠lanku obravnavamo potencialno rabo pe≠i za ∫ganje keramike v zahodni Sloveniji v
starej∏i ∫elezni dobi. Ker arheolo∏ko ∏e niso bile izkopane, je njihova uporaba predvidena na pod-
lagi posrednih kazalnikov, kot so na≠in ∫ganja in poskusi s podro≠ja arheologije poskusov. Namen
raziskave je prepoznati razloge za slabo ohranjenost pe≠i na tem obmo≠ju. Na vzorcih, ki smo jih
pridobili iz arheolo∏kih poskusov in na arheolo∏ki keramiki, smo merili navidezno magnetno suscep-
tibilnost, izvedli petrografske in mineralo∏ke (rentgenska difrakcija) analize. Rezultati teh analiz so
pokazali na pomembnost upo∏tevanja ≠asa ∫ganja kot merila pri opazovanju ∫galnega procesa in
uporabi enoprostornih pe≠i za ∫ganje keramike, ≠eprav ∏e niso bile odkrite. 
KEY WORDS – pottery; firing process; experimental archaeology; pottery kiln; ceramic technology;
apparent magnetic susceptibility AMS; X-ray diffraction XRD; Early Iron Age; Kras; Slovenia
KLJU∞NE BESEDE – keramika; proces ∫ganja; arheologija poskusov; pe≠ za ∫ganje keramike; tehno-
logija; navidezna magnetna susceptibilnost; rentgenska difrakcija XRD, starej∏a ∫elezna doba; Kras;
Slovenija
?ganje lon;enine v starej[i /elezni dobi
v zahodni Sloveniji
DOI> 10.4312\dp.49.20
Pottery firing in the Early Iron Age in western Slovenia
389
1978–1979.79, 82), and become hard and resistant
to decay (Rice 2005.55, 80). The colour change is re-
lated to the presence or absence of iron minerals
(chlorites, micas, Fe-oxides/hydroxides, sulphides)
in the clay. In the are discussed in this study the
clays are very rich in iron, which usually causes the
vessels to turn red (oxidation atmosphere) or grey
and black (reduction atmosphere) (cf. Maritan 2018.
206). The colour can also be affected by the pres-
ence of organic material, which converts to carbon
and oxidizes into CO2 in the presence of sufficient
oxygen. This change occurs at a temperature of about
800°C and can be recognized by a change in colour
(grey/dark grey when carbon is present and cream/
reddish when carbon is oxidized) (Gliozzo 2020.26).
During firing, structural changes also occur in the
minerals in the clay (Cuomo di Caprio 1985.130;
Levi 2010.112). The thermal stability of the mineral
phase and the changes induced by heat depend on
numerous factors, such as grain size, the mineralogi-
cal and chemical composition of inclusions and tem-
per, presence of aplastic inclusions, presence of or-
ganic material, position in the vessel, the position
of the vessel in the kiln, the soaking time, and cool-
ing (Gliozzo 2020.5).
What changes occur during the firing process and
which of them are relevant for the pottery of the dis-
cussed area? Hydration begins at different tempera-
tures, depending on the heating and the type of clay
minerals (e.g., illite 300–600°C), but the mixing of
clays can lower it (Rice 2005.87–88). Carbon oxi-
dation of carbon starts at 200°C and burns out com-
pletely between 600 and 750°C or at least just be-
low 800°C (Cuomo di Caprio 1985.131; Levi 2010.
121; Gliozzo 2020.26). Experiments showed that
the main loss of organic material (the use of barley
straw) in daub and kilns occurs between 200 and
300°C, with the final loss at about 400°C (Macphail,
Goldberg 2018.235). Between 675 and 870°C, cal-
cite decomposes completely into calcium oxide, with
cell volume decreasing and crystal size increasing
(Gliozzo 2020.6). Above 800°C, complex aluminosi-
licates form and the phase of sintering begins (Levi
2010.121), which is lower for carbonate clay (around
800°C). Hence, we cannot develop a unified phase
diagram for the firing process (Gliozzo 2020.5). The
presence of calcium carbonate contributes to a low-
er sintering temperature because lime acts as a flux,
causing vessels with admixed calcium carbonate to
sinter faster (Maggetti et al. 1984; Shoval 2016.12).
In highly processed deposits, a fired mineral is pre-
sent as rubefied mineral inclusions ranging in size
the pottery and samples from archaeological experi-
ments, we will try to reveal the features of the pot-
tery associated with the firing process, which will in-
directly help us identify structures for the firing of
pottery.
Firing is one of the most important steps in pottery
production, as it involves the transformation of clay
into ceramics. Due to the complexity of the produc-
tion process of pottery vessels, from the raw mate-
rial to the final product, the concept of the ceramic
chaîne opératoire has recently developed in cera-
mic analysis (Lemonnier 1993; Roux 2016.104–
107). Based on such observations, we try to identi-
fy technological traditions and patterns of certain
technical traits (cf. Roux 2016.104, 112). By includ-
ing the ceramic chaîne opératoire approach, cera-
mic experimental archaeology has gained a more
solid methodology (Jeffra 2015. 141), but only if
when the principle of so-called controlled compar-
ison is considered (Roux 2016. 7). Until the advent
of experimental archaeology and scientific analyses,
the process of pottery firing was actually the least
known technological process in the ceramic chaîne
opératoire (Rado 1988.92). We will attempt to an-
swer the question of what type of structures were
used for firing pottery in western Slovenia in the
Early Iron Age by integrating data from the macro-
scopic and microscopic analyses of the pottery mass
and firing technology. The data will be acquired from
experimental archaeology, measurements of appar-
ent magnetic susceptibility (AMS), and with the re-
sults of mineralogical analyses (X-ray diffraction).
The firing process
In the past, people had to rely on personal experi-
ence with firing, which in practice probably meant
conducting numerous successful and unsuccessful
experiments, as evidenced by the considerable over-
fired vessel waste at archaeological sites (Cuomo di
Caprio 1985.130). Today, laboratory and archaeolo-
gical experiments are carried out, adding signifi-
cantly to the knowledge and, above all, to the un-
derstanding of technological processes, which are
usually different under controlled laboratory condi-
tions (cf. Thér 2014.96).
After clay transforms into ceramics during the firing
process (Cuomo di Caprio 1985.125), a series of
chemical and physical reactions occur affecting the
hardness, permeability, porosity, and mineral com-
position of the final product. The products become
impermeable, change colour, and lustre (Heimann
Manca Vinazza, Matej Dolenec
390
from silt to sand-size. The presence of these materi-
als provides increased magnetic susceptibility, whe-
reas iron-free minerals are not rubefied and there-
fore magnetic susceptibility is naturally high (Mac-
phail, Goldberg 2018.235).
Iron oxides were frequently used for coatings, espe-
cially for the so-called ceramica zonata, which is
typical for the Early Iron Age in a large area, rang-
ing from northern Italy (Este, Padua) to Slovenia.
Examples of so-called ceramic situlae from Slovenia
are mostly considered imports (cf. Grahek 2018.
315). Red slips are also typical of other vessel types
(e.g., Dolenjska region in south-eastern Slovenia;
Dular 1982.90). Iron oxide haematite (Fe2O3) pro-
vides a red or reddish colour, while magnetite (Fe3O4)
provides grey, blue, green, and grey-brown colours,
and in the reduction, black (Heimann 1978–1979.
86; Rice 2005.334–336).
The firing atmosphere controls the partial pressure
of oxygen, which is higher in the oxidizing atmos-
phere. By leading the firing, we change the firing
phases (Heimann 1978–1979.86). In an oxidizing
atmosphere, complete firing occurs. We need dry
firewood and an air supply to achieve the combus-
tion of organic matter and the decomposition of sul-
fides if the latter is present. In a reduction atmo-
sphere, incomplete firing happens. We close the air
supply and pile organic material into the kiln (e.g.,
horse hooves, straw, etc.), which may be slightly
moist (Cuomo di Caprio 1985.126, 131).
In prehistory, different structures for firing pottery
were known. The basic division is into firing in the
open (bonfire) and firing in a kiln. In a bonfire, the
maximum temperature is reached quickly (approx.
10–50 minutes, usually 20–30 minutes), while firing
in a kiln takes longer (approx. 60 minutes to 11–12
hours). In a bonfire, the soaking time at maximum
temperature is shorter (a few minutes) than in a kiln
(up to 30 minutes). Oxidative and reductive atmo-
spheres can be achieved in both, yet the latter is
much more controlled in two-chamber kilns with a
perforated floor, especially the exchange. Cooling
takes less time in a bonfire (a few minutes to 1
hour), while it is slower in the kiln (1–4 days), and
firing in a bonfire also takes less time than firing
in the kiln (Gliozzo 2020.2–3).
Any natural clay type can be fired at low tempera-
tures, i.e. below 800°C, but the lowest possible tem-
perature for firing pottery is 500°C (Rye 1981. 16,
96). The data shows that prehistoric pottery was
mostly fired between 550 and 650°C or at the most
up to 750–850°C. Analyses from the field of experi-
mental archaeology generally reveal that tempera-
tures of 950°C and even 1100°C could be reached in
the kilns known in the Neolithic (Kovárník 1999.
315–317). Nevertheless, it was found that the soak-
ing time is of greater importance than the maximum
firing temperature (Gosselain 1992.244, Fig. 1). Fur-
thermore, it was also found that the temperature
of the core of the vessel burned in a bonfire is not
unified and that a temperature difference occurs be-
tween the outer surface and the fracture up to
220°C. The latter was also confirmed in the exam-
ple of vessels fired in a kiln (Maggetti et al. 2011;
Gliozzo 2020.4). Consequently, it is necessary to
examine the question of which part of the pottery
production is associated with a particular firing
structure (Thér 2014.78) or which forms or types of
vessels were fired in which structure (Gliozzo 2020.
27). Based on 72 archaeological experiments, Ri-
chard Thér (2014) showed that there are no diffe-
rences between firing structures at temperatures up
to 1050°C when thermal profiles are observed and
that the firing method is more important than the
firing structure (Thér 2014.79–80, 93). Later, he
tried to find out if it was possible to distinguish be-
tween products fired in a bonfire and those fired in
a kiln by observing the thermal gradient of maxi-
mum temperature (XRD analyses) in the core of the
vessel and in the outer and inner surfaces. He disco-
vered that the difference between the maximum
temperature between the outer surface and the core
was 100–200°C when fired in a bonfire, and be-
tween 0 and 50°C when fired in a kiln (Thér et al.
2018.1144–1145, 1169). This means that we have
finally found a way to distinguish firing in bonfire
from firing in a kiln.
Archaeological background
In general, only a few pottery firing structures from
the Bronze and Iron Ages have been found in the
area of present-day Slovenia. Until the end of the
Early Iron Age, only single-chamber kilns are known
(e.g., Oloris near Dolnji Lako∏ from the Late Bronze
Age, Dobrava near Oto≠ec (Horvat πavel 1988–1989.
130–131; Dular et al. 2002.37, T. 24–25; Josipovi≤
et al. 2015.16, Figs. 11–12). While a two-chamber
kiln with a perforated floor was found at the Late
Iron Age site Hajdina at Ptuj (Tomani≠ Jevremov,
Gu∏tin 1996.271, Fig. 4). Generally, two-chamber
kilns were used much earlier, as they appear indivi-
dually in Italy no later than in the Middle Bronze
Age (Bronzo recente), while their use increases in
Pottery firing in the Early Iron Age in western Slovenia
the Early Iron Age1 (Levi 2010.117). To date, no fir-
ing structures have been found in western Slovenia.
All the consumptions in the literature are still based
on indirect data, on the macroscopic analysis of the
technology of pottery firing from three hillforts in
the Kras, Tabor near Vrab≠e, Tomaj, and πtanjel (Fig.
1). In addition to stratigraphic data, also radiocar-
bon dates are also available (Vinazza 2021.430–
433, Fig. 5). The Tabor site near Vrab≠e belongs to
the transition from Late Bronze to Early Iron Age
(Phase 1; 11.–10. cent. BC) and Early Iron Age
(Phase 2; 8.–7. cent. BC). The Tomaj site belongs to
the Early Iron Age (6.–5. cent. BC) and πtanjel be-
longs to the end of Early Iron Age (6th and 5th cent.
BC). The macroscopic analysis indicated that at the
end of the Late Bronze Age (Ha A2/B1) the major-
ity of pottery was fired in a reduction atmosphere
(e.g., Tabor near Vrab≠e 38.2%). In the 8th and 7th
cent. BC (Ha C0–C2) the ratio begins to change as
less and less reductive firing take place, only 4.8%
at Tabor near Vrab≠e and 25% at Tomaj. This trend
continues until the end of the Early Iron Age, as
shown by the analysis of pottery from πtanjel (7.1–
23.9%). It should be emphasized that incomplete
oxidation firing predominates throughout at all the
sites, with the proportion of oxidation firing in-
creasing only at the end of the Early Iron Age in the
case of πtanjel (38.7%) (ibid. Tab. 3). Changes are
also observed in the preparation of the pottery paste.
The macroscopic analysis of pottery mass confirms
the findings in the wider area of north-eastern Italy
and western Slovenia, as a temper of calcite prevails
at the end of the Early Iron Age, while pottery is
more frequently fired in oxidation atmosphere (Sa-
racino 2014.104–122, 131–132; Grahek 2018.311;
cf. Vinazza 2021.433, Fig. 1).
Certain sites in Kras and in the Poso≠je region2 re-
vealed individual examples of the so-called red-black
painted pottery (Este style, Ita. ceramica zonata).
Case analyses from Poso≠je region, from Most na So-
≠i, showed the presence of iron and manganese to
achieve the red and black colour of coating on the
pottery (Grahek 2018.313–314). This final colour
effect is the result of the so-called three-stage fir-
ing (ORO), in which oxidation and reduction firing
Fig. 1. Sites mentioned in the text (© Google Earth Pro).
1 Ponte San Marco (Poggiani Keller 1994.76), Forcello di Bagnolo S. Vito (Rapi et al. 2019.107), Montedoro di Scapezzano, Mate-
lica (Macerata), Marche, Cesena, Foro Annonario (Gasparini, Miari 2017.24), Padova, Ex Brolo (Iaia, Moroni Lanfredini 2009.65,
68, 70).
2 Repentabor (7th and 6th cent. BC) (Maselli Scotti 1978–1981.Fig. 9.1); Repni≠ from the 7th and 6th cent. BC (Maselli Scotti 1983.T.
54, 214), πtanjel (Vinazza 2011.T. 9.103), and Most na So≠i (Grahek, Ko∏ir 2018.315).
391
Manca Vinazza, Matej Dolenec
392
atmospheres exchange (cf. Aloupi-Siotis 2020.3, 5).
This is made possible by the two-chamber kilns with
a separated fireplace and firing parts, which have
been already mentioned several times before. One
of the most important parts of such kilns is the per-
forated floor. When determining this type of kilns
based on the perforated floor, we need to be careful
since such perforated floors were also used in, for
example, salt extraction in the area under study in
this work.3 Such a ceramic situla was also found at
the πtanjel site (Vinazza 2011.T. 9. 103), and is part
of the present study. 
Methods and sampling
For the present study, which is first of this kind in
the studied area, we analysed 18 samples. The ar-
chaeological pottery comes from two hillforts, Tabor
near Vrab≠e and πtanjel (for more details, see Vinaz-
za 2021.422–425). Other samples were produced
during archaeological experiments. Besides experi-
mental archaeology, we also carried out additional
analysis, such as AMS measurements, ceramic petro-
graphy analysis, and X-ray diffraction analysis (see
Tab. 1). 
We conducted experiments on the construction and
use of a single-chamber kiln in order to better un-
derstand why the remains of kilns are so poorly pre-
served in the archaeological record in the studied
area, and to get samples for observing changes in
material under different temperatures. The kiln was
built on the model of a Late Bronze Age kiln from the
Oloris site near Dolnji Lako∏ (Horvat πavel 1988–
1989.130–131). We were thus able to observe its
manufacture, material, construction, and use during
firing, as well as its decay.
Clay,4 straw, and hazel branches were used for the
construction of the kiln (16.6.2020). We prepared
the mixture of clay, water, and straw (40%). The
bottom of the 10cm deep pit was first covered with
a clay mixture. After that, a construction from hazel
branches, which was covered on the outside with
clay strips of 20x15x5cm, was built. Seven people
built the kiln in 5 hours (the preparation of the ma-
terial and the construction). After 4 days, the kiln
was dried by burning spruce chips (we used up
12kg), which took 6 hours and 30 minutes. After
that, the kiln was ready for pottery firing.
The firing of the pottery took place after two months
(28.8.2020). The kiln was loaded with 57 vessels
that we formed from different local clays.5 Two ther-
moelements6 were installed onto the kiln, one along
the kiln wall and the other in the centre, just below
the vessels. We wanted to understand if there was
any change in temperature in the kiln during firing.
To obtain different types of data and their possible
application to the archaeological remains, we mea-
sured the AMS of the kiln.7
The magnetic susceptibility of the ground8 or sed-
iment is determined by the amount of magnetic mi-
nerals present. During burning, the magnetic suscep-
tibility increases because iron minerals are bound. If
the ground or the sediment does not contain iron
minerals, the magnetic susceptibility is not high. The
iron content depends on the geological background
(Goldberg, Macphail 2006.350–351; see also Mu∏i≠
1999.363). If magnetite is present in the clay, mag-
netic susceptibility is naturally high (Macphail, Gold-
berg 2018.236). Measurements were taken in the
laboratory on soaked clay (the Ren≠e clay) (mixed
with water and straw: 0.850) from which the kiln
was built, on samples from the kiln after drying, and
on samples from the kiln after firing (Fig. 3). The va-
lues given are average values.9
Clay from Ren≠e that was used for building the kiln
was also fired in a controlled atmosphere. We have
3 A perforated floor from the Ellerji hillfort has been interpreted several times before as the remains of salt production (Lonza 1981.
T. 44–45; Zendron 2018), while the remains of a perforated floor from the Monkodonja site in Istria were among the earliest in
the wider area (Early and Middle Bronze Age) (Mihovili≤ 2020.36–39, Fig. 31). This means that they appear significantly earlier
than in the entire Italic peninsula, which indicates the supra-regional role of Monkodonja.
4 The Ren≠e deposit: GKY 396454, GKX 83339.
5 Gri∫e: GKY 417619, GKX 69497; Veliki Dul: GKY 411812, GKX 70871; Lukovica: GKY 476504, GKX 112322, and Ren≠e: GKY
396454, GKX 83339.
6 Thermoelement type MTC500 with a Ni-Kr-Ni tip.
7 The Kappameter KT-7 (GF Instruments) instrument was used.
8 Values of AMS were measured on various samples of clays and present the results that do not enable simplified conclusions, since
the values range from 0.1 to 8·10–3SI. Location near Tupel≠e (GKY 407902, GKX 73627): clay to 6–8·10–3SI; Vrab≠e (GKY 409555,
GKX 77491): clay 0.063–0.207·10–3SI; Veliki Dul (GKY 409555, GKX 77491): 0.532–0.666·10–3SI; Ostri vrh (GKY 409555, GKX
77491): 0.766–0.966·10–3SI.
9 Three measurements were taken for every point and the average value was calculated.
Pottery firing in the Early Iron Age in western Slovenia
393
Ta
b.
 1
. S
am
pl
es
 1
–1
2 
ar
e 
pa
rt
 o
f 
th
e 
pr
es
en
t 
st
ud
y.
Sa
m
pl
e 
ID
Pe
tr
ol
ab
 I
D
So
ur
ce
D
es
cr
ip
tio
n
C
la
y
A
dd
M
an
ip
ul
at
io
n
Fi
ri
ng
M
et
ho
d
in
fo
rm
at
io
ns
Sa
m
pl
e 
1
20
20
-6
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
N
ec
k 
of
 t
he
 p
ot
U
nk
no
w
n
U
S 
52
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
si
te
 {
ta
nj
el
X
R
D
 a
na
ly
si
s
Sa
m
pl
e 
2
Ex
pe
ri
m
en
t
R
im
 o
f t
he
 b
ow
l
R
en
;e
A
dd
ed
 w
at
er
67
0
 °
C
A
rc
h.
 e
xp
er
im
en
t< 
ce
ra
m
ic
 p
et
ro
gr
ap
hy
an
al
ys
is
< X
R
D
 a
na
ly
si
s
Sa
m
pl
e 
3
20
22
-3
Ex
pe
ri
m
en
t
B
ot
to
m
 o
f t
he
 k
iln
R
en
;e
A
dd
ed
 w
at
er
 a
nd
 s
tr
aw
67
0
 °
C
A
rc
h.
 e
xp
er
im
en
t m
ac
ro
sc
op
ic
 te
ch
no
-
lo
gi
ca
l a
na
ly
si
s<
 X
R
D
Sa
m
pl
e 
4
20
21
-2
4
Ex
pe
ri
m
en
t
W
al
l o
f t
he
 k
iln
R
en
;e
A
dd
ed
 w
at
er
 a
nd
 s
tr
aw
67
0
 °
C
A
rc
h.
 e
xp
er
im
en
t< 
ce
ra
m
ic
 p
et
ro
gr
ap
hy
an
al
ys
is
< X
R
D
 a
na
ly
si
s
Sa
m
pl
e 
5
Ex
pe
ri
m
en
t
C
hi
m
ne
y
R
en
;e
A
dd
ed
 w
at
er
 a
nd
 s
tr
aw
67
0
 °
C
A
rc
h.
 e
xp
er
im
en
t< 
m
ac
ro
sc
op
ic
 t
ec
h-
of
 t
he
 k
iln
no
lo
gi
ca
l a
na
ly
si
s<
 X
R
D
Sa
m
pl
e 
6
Ex
pe
ri
m
en
t
cu
be
R
en
;e
A
dd
ed
 w
at
er
60
0
 °
C
A
rc
h.
 e
xp
er
im
en
t< 
m
ac
ro
sc
op
ic
 t
ec
h-
no
lo
gi
gc
al
 a
na
ly
si
s<
 X
R
D
Sa
m
pl
e 
7
Ex
pe
ri
m
en
t
cu
be
R
en
;e
A
dd
ed
 w
at
er
80
0
 °
C
A
rc
h.
 e
xp
er
im
en
t< 
m
ac
ro
sc
op
ic
 te
ch
no
-
lo
gi
gc
al
 a
na
ly
si
s<
 X
R
D
Sa
m
pl
e 
8
C
la
y
N
o 
m
an
ip
ul
at
io
n
R
en
;e
0
0
A
rc
h.
 e
xp
er
im
en
t< 
m
ac
ro
sc
op
ic
 t
ec
h-
no
lo
gi
ca
l a
na
ly
si
s<
 X
R
D
Sa
m
pl
e 
9
20
20
-1
0
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
N
ec
k 
of
 t
he
 p
ot
U
nk
no
w
n
U
S 
52
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
 
si
te
 {
ta
nj
el
X
R
D
 a
na
ly
si
s
Sa
m
pl
e 
10
20
20
-1
0
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
N
ec
k 
of
 t
he
 p
ot
U
nk
no
w
n
U
S 
52
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
 
si
te
 {
ta
nj
el
X
R
D
 a
na
ly
si
s
Sa
m
pl
e 
11
20
20
-1
0
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
N
ec
k 
of
 t
he
 p
ot
U
nk
no
w
n
U
S 
52
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
 
si
te
 {
ta
nj
el
X
R
D
 a
na
ly
si
s
Sa
m
pl
e 
12
20
22
-2
Ex
pe
ri
m
en
t
R
im
 o
f t
he
 b
ow
l
R
en
;e
A
dd
ed
 w
at
er
 a
nd
 c
al
ci
te
67
0
 °
C
A
rc
h.
 e
xp
er
im
en
t< 
m
ac
ro
sc
op
ic
 t
ec
h-
no
lo
gi
ca
l a
na
ly
si
s<
 X
R
D
Sa
m
pl
e 
13
Ex
pe
ri
m
en
t
N
o 
m
an
ip
ul
at
io
n
R
en
;e
A
dd
ed
 w
at
er
 a
nd
 s
tr
aw
67
0
 °
C
A
rc
h.
 e
xp
er
im
en
t< 
m
ac
ro
sc
op
ic
 t
ec
h-
no
lo
gi
ca
l a
na
ly
si
s<
 X
R
D
Sa
m
pl
e 
14
20
22
-1
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
B
ot
to
m
 o
f
U
nk
no
w
n
U
S 
28
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
 
si
te
 {
ta
nj
el
ce
ra
m
ic
 s
itu
la
ce
ra
m
ic
 p
et
ro
gr
ap
hy
 a
na
ly
si
s
Sa
m
pl
e 
15
20
22
-4
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
Si
lo
s
U
nk
no
w
n
U
S 
28
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
 
si
te
 {
ta
nj
el
ce
ra
m
ic
 p
et
ro
gr
ap
hy
 a
na
ly
si
s
Sa
m
pl
e 
16
20
20
-1
8
C
la
y
N
o 
m
an
ip
ul
at
io
n
{t
an
je
l
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
ce
ra
m
ic
 p
et
ro
gr
ap
hy
 a
na
ly
si
s
Sa
m
pl
e 
17
20
20
-1
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
R
im
 o
f t
he
 p
ot
Ta
bo
r 
ne
ar
U
S 
18
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
si
te
Ta
bo
r 
ne
ar
 V
ra
b;
e
V
ra
b;
e
ce
ra
m
ic
 p
et
ro
gr
ap
hy
 a
na
ly
si
s
Sa
m
pl
e 
18
20
20
-1
2
A
rc
ha
eo
lo
gi
ca
l p
ot
te
ry
,
R
im
 o
f t
he
 p
ot
Ta
bo
r 
ne
ar
U
S 
9
0
0
M
ac
ro
sc
op
ic
 t
ec
hn
ol
og
ic
al
 a
na
ly
si
s<
 
si
te
Ta
bo
r 
ne
ar
 V
ra
b;
e
V
ra
b;
e
ce
ra
m
ic
 p
et
ro
gr
ap
hy
 a
na
ly
si
s
Manca Vinazza, Matej Dolenec
394
prepared two samples (Tab. 1.6, 7) by adding water
to the clay and firing them at the temperatures of
600 and 800°C in an electrically operated kiln (70kW,
with Shimaden FP93 programme controller).
For ceramic petrography analysis, we chose samples
on the basis on the results from the macroscopic
technology analysis. We chose this method for vari-
ous reasons. We wanted to observe changes in pot-
tery recipes between Late Bronze and Early Iron
Ages at the sites Tabor near Vrab≠e and πtanjel,
changes during different temperature stages com-
paring archaeological material and material from
our archaeological experiments (see Cultrone et al.
2001.629), and compare pottery paste with local
clays (Quinn 2015) in the case of the πtanjel site.
The selected samples (Tab. 1) were prepared as po-
lished thin sections, 30 microns thick, mounted on
glass slides and analysed under the polarizing light
microscope, Zeiss Axiocam 305 colour, using standar-
dized descriptions (Quinn 2015; 2022. 98–124).
X-ray diffraction is used to characterize archaeologi-
cal pottery in terms of the minerals present and
their relative abundance and allows the characteri-
zation of minerals that cannot be recognized in thin-
section petrography, such as clay minerals or new
phases formed during firing. The XRD analysis of mi-
nerals present in pottery can help identify the tem-
perature interval at which pottery was fired, as cer-
tain minerals are indicators of changes that occur
during the firing process – examples include haema-
tite, magnetite, cristobalite, mullite, calcite, montmo-
rillonite, illite, vermiculite, and feldspars (Quinn,
Benzonelli 2018.2; Amicone et al. 2020.526–527).
The mineral composition of the pottery samples
was determined using a Philips PW3710 X-ray dif-
fractometer. It was recorded at a voltage of 40kV
and a current of 30mA in the range from 3° to 70°
2q at a speed of 3°/min. The wavelength of the Cu
Ka X-ray wavelength was 1.5460Å. A secondary gra-
phite monochromator and a proportional counter
were used. The detection limit for minerals was be-
tween 0.5 and 3%. The Rietveld method was used to
quantify the mineral phases. Diffractograms of the
recorded samples were processed using the compu-
ter program X’Pert HighScore Plus 4.8v and the PAN-
ICSD database. 
Results
In carrying out the archaeological experiments, fir-
ing in the kiln took a total of 10 hours. First, we start-
ed heating slowly at the entrance and only began
to increase the temperatures after four hours (Fig.
2). Initially, the temperature along the kiln wall in-
creased more rapidly than in the centre, while from
500°C onward the temperature in the centre started
rising more rapidly than along the wall. We were
burning fuel in the front and to the left and right of
the vessels. The drop in the temperature along the
kiln wall (Fig. 2.15, 35) is the result of clearing the
charcoal from the kiln. During firing up to 0.75m3
of beech wood was burned and a temperature of
670°C was reached. The soaking time at this tempe-
rature lasted 30 minutes. The total time of the firing
process was 10 hours. After this time, we did not
measure the temperature further. On the third day
(31.8.2020), we opened the kiln and took out 56
vessels (98% of them were successfully fired, un-
broken). To date, some of the vessels have been used
for cooking over an open fire seven times and are
still undamaged. 
The AMS measurement results show that tempera-
tures that would affect the increased AMS are not
reached during drying. The change occurs at higher
temperatures, but mainly at the areas where the kiln
surface was in direct contact with the fire. We thus
have the highest values at locations where the fire
was burning (9.524·10–3SI, 12.54·10–3SI, and 17.91·
10–3SI), and on the inside of the chimney (15.21·
10–3SI) where the fire directly touched the kiln. High
values were also recorded on the inner wall of the
kiln (5.852·10–3SI) and on the outer side in the cen-
tre of the kiln (7.316·10–3SI), where the kiln wall
was thin. From this part towards the ground, the va-
lues decrease, while at the same time the kiln walls
were significantly thicker towards the bottom.
The next goal of our study was the observation of
the kiln’s decay. The kiln was covered over a month
after firing and then we left it in the open air, under
the sun, rain, and snow. The dome collapsed half a
year later, on 9.12.2020. The floor of the kiln was
still as hard as when the firing was finished and
covered with the ruins of the dome. Pieces of the
dome and kiln walls were still very compact. The
kiln walls were preserved only at the edge of the
kiln. Over the next six months (Fig. 4.A), the most
compact parts of the kiln softened and gradually
began to merge into the depositional matrix. On
31.1.2022 (Fig. 4.B), parts of the kiln wall were still
standing, but softened, while the kiln floor was still
equally as hard as it had been six months earlier.
Major visible changes occurred over the next five
months (Fig. 4.C). The preserved walls weakened,
Pottery firing in the Early Iron Age in western Slovenia
395
and the outer and inner edges were only sporadi-
cally preserved. Most of the dome turned into the
depositional matrix, while the underlying slab was
also preserved, being protected by the material. To-
day (October 2022) more and the more deposition-
al matrix is forming, and the kiln floor is still hard
as it was before. 
The analysis of pottery thin sections from Tabor
near Vrab≠e shows that at the transition to the Late
Bronze Age grog (20%) predominates as a temper.
We could detect different types of grog in one ves-
sel (20%); there is some organic temper (2%) and
some planar voids. Individual calcite (1%) and
quartz (5%) grains we understand as inclusions (Fig.
6.1; Tab. 1.17). Slightly later, in the 8th and 7th cent.
BC (Phase 2), the pottery paste changes (Fig. 6.2;
Tab. 1.18) and calcite predominates as the only tem-
per (30%). There are a lot of visible voids and some
small parts of organic matter (>1%). Sharp calcite
edges (rhombohedral cleavage) indicate intentional
crushing (Fig. 6.2–3). Calcite also predominates as
a temper in the final stage of the Early Iron Age, in
the 6th and 5th cent. BC (40%), as pottery from πta-
njel shows (Tab. 1.1). The difference is visible in the
size of the calcite temper. The grains are bigger in
pastes from the 8th and 7th cent. BC than in those
from the 6th and 5th cent. BC. In the later period
there is a finer temper of calcite. The temper is still
poorly sorted, but in comparison with older materi-
al there are no voids.
The kiln wall pottery thin section (Fig. 5) corre-
sponds to the basic characteristics of such objects
found at archaeological sites. Here we have in mind
the main micromorphological features of mudbricks,
such as the presence of organic elongated fragments
and randomly oriented channels and voids, reflect-
ing the addition of straw into the otherwise very
compact structure during the preparation (cf. Frie-
sem et al. 2018.99–100). In our case (Sample 4) the
are many planar voids and channels, indicating that
straw is the only temper used for kiln paste. Other
features are inclusions, such as Fe-oxides, clay pel-
lets, quartz grains, and some other opaque minerals.
In order to determine the origin of the classic situ-
la from πtanjel and thus the possibility of the pres-
ence of the two-chamber kilns, we conducted a com-
parative study of the pottery masses using pottery
thin sections. We took samples of local clay (Fig. 7B;
Tab. 1.16), silos10 (Fig. 7.D; Tab. 1.15), and pottery
from the πtanjel site. One from the local form (Fig.
7.A; Tab. 1.1) and one from a presumably imported
ceramic situla (Fig. 7.C; Tab. 1.14). Silos, such as ce-
ramic rings, loam weights, and house plaster, are ge-
nerally made from the clay closest to the site, mak-
ing them a good comparison for determining local/
imported products. Even a quick look at the pottery
thin section of a silo (Fig. 2.4) and the ceramic sit-
ula (Fig. 7.3) shows that we are dealing with diffe-
rent clays. The silo contains muscovite/illite (up to
20%) and polycrystalline and monocrystalline quartz
(25%), while the muscovite/illite is not present in
the ceramic situla. The latter also did not include
clasts of trachyte, which is typical of such forms from
the Euganean area (see Saracino 2014.120, 144).
The clay matrixes of the local vessels, the silo, and
the local clay, sampled near πtanjel are very close in
composition, while the ceramic situla stands out.
Fig. 2. Measurements of temperature in the kiln during firing. Left: along the wall, right: at the bottom
of the kiln, under the vessels.
10 A silo petrographic thin section (Fig. 2.4) indicates the presence of certain carbonates, which are unchanged, meaning that firing
took place at a temperature from 675 to 870°C. The same is true for the pottery from Ren≠e (Sample 2), fired at 670°C. The silos
as such is also solid (7 according to the Mohs scale), which reflects firing at a high enough temperature and at the same time
changes the idea that such pottery forms were fired at low temperatures (Vinazza 2016.7).
Manca Vinazza, Matej Dolenec
396
The XRD analyses were performed on 12 samples
(Tab. 1.1–13). The objective of the analysis was to
determine the comparison of the XRD analysis re-
sults with the firing temperature in the kiln, which
was measured with thermoelements during firing.
We also tried to show that the firing temperatures
of individual kiln parts do not reflect the tempera-
ture of the pottery firing, which consequently cannot
be applied to the archaeological material. Third, fol-
lowing the lead of Thèr (2020), we sought to
determine whether we could detect differences
between the results of XRD analysis at the fracture
and on the outer surface of the pottery, and thus
determine the use of a bonfire and/or kiln at the
site. The analyses were carried out on the samples
of the kiln from the Ren≠e clay, which is of the
illite-chlorite type (Rokavec 2014.35), and on the
pottery from the πtanjel site, which belongs to the
end of the Early Iron Age (Tab. 1; Fig. 8).
Ren≠e clay (Samples 2–8, 12)
Clay from Ren≠e (Sample 8) has a higher amount of
kaolinite (Fig. 8) which is not present in the other
samples (Samples 2–5), meaning that the latter were
fired at over 550°C. Comparing the parts of the kiln
(floor/walls/chimney), most kaolinite is found in the
kiln walls (Sample 4), less in the floor (Sample 3),
while no kaolinite is present in the sample from the
chimney (Sample 5). It is therefore understandable
that most of it is in the wall where the temperature
in the kiln was the lowest. Sample 6 (firing at 600°C)
contains very little kaolinite, while Sample 7 (firing
at 800°C) and Sample 12 (firing at 670°C) contain
no kaolinite. Illite, which begins to decompose at
900°C, is present in all samples, while only Sample 7
contains less because it was fired at 800°C. Quartz is
also present in all samples. Calcite is also present in
Samples 6 and 8, which we attribute to its natural
occurrence in the clay. Sample 12 (Fig. 8) has an ele-
Fig. 3. The AMS measurement points were chosen
on various parts of the kiln (in the centre) and of
the individual parts (kiln wall (A–C), chimney
(D–F), and kiln floor (G–H)).
Pottery firing in the Early Iron Age in western Slovenia
397
vated calcite value, which we attribute to the inten-
tional addition of the temper of calcite to the clay,
which is also confirmed from pottery thin sections.
It is no longer present in Sample 7, as it begins to
decompose above 670°C. Dolomite is found in Sam-
ples 6 and 8, but in small amounts and is no longer
present in Sample 12.
πtanjel pottery (Samples 1, 9–11)
Calcite is present in all samples indicating that the
pottery was fired at temperatures below 870°C, at
which calcite decomposes completely. Sample 1 (Fig.
8) has an increased value of calcite, which we attri-
bute to the intentional admixture of the temper of
the calcite to the clay (Fig. 8), which is also confirm-
ed by pottery thin sections. At the same time, kaoli-
nite is no longer present, indicating that the pottery
was fired at over 550°C. The samples from πtanjel
contain very little illite, which is due to the minera-
logical composition of the clay. A comparison of the
calcite in the vessel’s core (Sample 10) and in the
outer (Sample 9) and inner surfaces (Sample 11)
shows that the vessel’s core contains more calcite.
Discussion
Archaeological finds that would indicate the firing
of the pottery in Kras and the Poso≠je region in the
Bronze and Iron Ages are not known for either a bo-
nfire or a kiln. There are at least two possible rea-
sons for this. First, slow sedimentation at Kras is
very problematic from a stratigraphical point of
view. In most cases, the sites have very thin archa-
eological layers and only rarely do we discover a
longer stratigraphic sequence (cf. Monkodonja in Is-
tria; Hänsel et al. 2015.75). The soil at Kras is char-
acterized by the bedrock, various limestones and do-
lomites, their decomposition and dissolution, and
the leaching of debris into relief depressions. On
karstified hills and in higher areas there is less soil,
while in depressions, e.g., dolinas (Habi≠ 1979.150),
there are uniform and thicker layers. The discussed
pottery originates from the hillfort sites of Tabor
near Vrab≠e and πtanjel (Vinazza 2021), where there
is in both cases less soil.
The second reason is connected with the firing struc-
tures and the question of how to recognize them in
order to understand the firing process. Structures
such as bonfires do not leave any significant traces
behind, and are thus difficult to discern. If we con-
sider a burned layer of soil, a large pile of plant char-
coal, wooden charcoal, burned-through soil, and
burned lumps of soil as the key indicators of the re-
mains of a bonfire for firing pottery (Guo 2017.
184), then some of the structures found at several
sites from Eneolithic to the Early Iron Age in cen-
tral and north-eastern Slovenia could be interpret-
ed as bonfires.11 We are still missing this kind of
data for the Kras area.
Fig. 4. A year’s decay of the kiln. A 27.07.2021, B
31.01.2022, C 16.06.2022.
11 The Eneolithic: Kalinovjek, SE 171, 174, 176, 178, 257, 259 (Kerman 2013.58, 59, 62); the Early Bronze Age; Nova tabla, PO 29,
PZ 24 (Gu∏tin et al. 2017.112, 115); the Middle and Late Bronze Ages: Nedelica pri Turni∏≠u SU 344/343, 372, 381 (πavel, San-
kovi≠ 2013.78), Svetje, SU 41/42 (Leghissa 2011.86); the Late Bronze Age: Pod Kotom – sever pri Krogu, SU 347 (Kerman 2011.
71); Orehova vas, SU 160M, 191A, 81R (Grahek 2015.53, 59, 88)); the Early Iron Age: Nova tabla, PO 223 (Gu∏tin et al. 2017.
127); Hotinja vas near Maribor, SU 271/272 (Gerbec 2015.43).
Manca Vinazza, Matej Dolenec
398
The situation is a different matter with kilns. They
decay in a certain phase, but their remains depend
on different situations. Today’s climate in the dis-
cussed area is too dry, and poorly fired structures
decompose into the matrix of the archaeological de-
posit (Amicone et al. 2020.522), and it is also pos-
sible that the space is reused at a later date. 
We believe one of the reasons why these kilns have
not been preserved is also due to the use of these
structures. Our archaeological experiments have
shown that different parts of kilns are exposed to
different temperatures, which is consistent with the
results of the AMS. The most exposed parts were the
kiln floor and the chimney. Higher values of the
AMS mean that these parts were fired better, which
affects the degree of preservation of these parts of
the kiln. In the exposure to different temperatures,
we see the reason for the poor preservation of the
kilns, which can be applied to the wider area.12 From
this, we can say that we can mistake the remains of
the kiln floor with, for example, a hearth. Hence we
believe that we should focus our attention on pos-
sible remains of an interlacement that could have
belonged to the former dome,13 which will signifi-
cantly contribute to the final interpretation of whe-
ther it is a kiln or a hearth.
Consequently, we believe that the firing tempera-
tures of vessels cannot be determined by analysing
the temperature of the parts of kilns. As already
mentioned, different values of AMS indicated diffe-
rent temperatures of the firing of different kiln parts.
Since kiln parts are usually randomly preserved, it
means we do not necessarily obtain the best-fired
part when sampling. Moreover, in the case of kilns
the soaking time plays an important role, since
bricks, for example, are fired for several days be-
fore they are properly fired. When macroscopically
observing the core of cubes made of Ren≠e clay (App.
1: Samples 6 and 7) it can be seen that the core is
still grey at 600°C, while at 800°C the grey part
shrinks.
Evidence of this is the results of the XRD analysis of
vessels and kiln parts from the Kra∏nja site in Slove-
nia, which showed that the vessels were fired at
about 800°C, while samples of the wall and bottom
of the kiln indicate a temperature of no more than
500°C (Ωibrat Ga∏pari≠ et al. 2014.232, 234).
We can also apply these results to pottery firing. As
Thér et al. (2018) have already shown, the soaking
time needs to be considered when comparing firing
in a bonfire with firing in a kiln.
Fig. 5. Panoramic view of a pottery thin section of the kiln wall. The voids are the result of the burned-
out organic material, straw. Photos taken under plain polarized light. 
12 Here we always need to compare AMS measurements of the local clays, since the values may depend on the natural composition
and the presence of, for example, magnetite.
13 We have found five pottery kilns at the roman site Otok pri Metliki in southeastern Slovenia. Above the perforated floor there
was a red layer full of small pieces of burned clay. There were no visible marks of the construction made with branches (see
Udov≠, Vinazza 2018.147–149).
Pottery firing in the Early Iron Age in western Slovenia
399
Fig. 6. Changes in the pottery recipes (petrographic thin sections and site phases (1 Late Bronze Age; 2
Early Iron Age; 3 end of Early Iron Age)) in combination with radiocarbon dates from the sites of Tabor
near Vrab≠e and πtanjel. Photos taken under plain polarized and cross polarized light. 
Manca Vinazza, Matej Dolenec
400
There are no differences in the mineralogical com-
position of the πtanjel pottery when comparing the
vessel’s core and inner and outer surfaces (Samples
9–11). We take the lack of variation in these values
as evidence that the pottery was fired in a kiln. The
calcite values have not changed, which means that
the decomposition of the calcite has not started at
a temperature that has not exceeded 850°C.
Here, we would like to point out that the increase of
calcite that was already shown by macroscopic tech-
nological analysis (Vinazza 2021) and confirmed
with pottery thin sections in this study, in pottery
from sites Tabor near Vrab≠e and πtanjel is not
linked to a particular vessel type, but is noted in va-
rious forms, such as pots, dishes, and lids. This
means the reason for the addition of calcite is not
only related to the functional properties, which in-
creases the resistance to thermal shock (Bronitsky,
Hamer 1986.95–99), but also to the firing process,
since calcite acts as a flux that allows carbonate clays
to be fired at lower temperatures (Shoval 2016.12).
Since calcite decomposes at a temperature of up to
870°C and since the XRD results for πtanjel pottery
show that the temperature did not exceed 870°C,
we assume that the use of kilns makes it easier to
control the temperature and thus the use of such an
amount of calcite.14
Finally, we analysed ceramic situla from πtanjel in
order to find confirmation of ORO firing of this type
of vessel and consequently the potential use of two-
chamber kilns with a perforated floor in the Kras
area. As the ceramic situla from πtanjel was not
made from the same clay, as the other samples show,
we see it as an imported vessel. Samples from Most
na So≠i from Poso≠je (Grahek, Ko∏ir 2018.309–311,
314–315; sample MNS D or Most 4) suggest the pos-
Fig. 7. A comparison of clay-matrix archaeological pottery – vessels (1, 3), with a silo (4) and clay from
the vicinity of πtanjel (2). Photos taken under plain polarized and cross polarized light.
14 This material is ubiquitous in the discussed area (see Jurkov∏ek 2013).
Pottery firing in the Early Iron Age in western Slovenia
401
sibility that some of the pieces were imported from
workshops in the Este area, while others are prob-
ably the product of local workshops. In our case, no
pieces of trachyte were found in the pottery mass,
which is typical for the Euganean area (see Saraci-
no 2014.144). We believe that the area of origin of
the ceramic situla from πtanjel is elsewhere and the
possibility of local workshops is still open to discus-
sion, since the XRD results also show no or a very
small amount of muscovite in pottery from πtanjel
(Fig. 8.samples 9, 10).
Conclusion
With the help of various research methods and sci-
entific analyses, we have tried to determine whether
the use of kilns for pottery firing can be expected in
the Early Iron Age in western Slovenia. The pottery-
manufacture technology of this period suggests this
possibility, and the same is true for the results of
XRD analysis, which do not reveal major tempera-
ture deviations between the outer surface and core
of the vessel, which means that the soaking time
was long enough to allow gradual and uniform fir-
ing of the vessels. The XRD analyses of the pottery
from πtanjel show that the temperature did not ex-
ceed 870°C, while the addition of calcite as a tem-
per, which did not decompose, suggests that the fir-
ing took place under controlled conditions, which
can be better controlled in a kiln (e.g., no sudden
temperature rise due to the wind blowing). The pre-
valence of oxidative firing, which is much more con-
trolled in a kiln, is also supported by the macrosco-
pic analysis of pottery in western Slovenia at the end
of the Early Iron Age. Based on the above, we as-
sume that in western Slovenia at the end of the
Early Iron Age (the 6th and 5th cent. BC) only single-
chamber kilns for the firing of pottery were known,
even though archaeological excavations have not
(yet) brought them to light. We need to point out
that a single-chamber kiln from the Early Iron Age
was found in the Dolenjska region (site Dobrava
near Oto≠ec), as mentioned above, but for the area
of Friuli Plain in Italy we still have no evidence. In
Fig. 8. Mineralogy distribution (XRD results).
Aloupi-Siotis E. 2020. Ceramic technology: how to charac-
terise black Fe-based glass-ceramic coatings. Archaeologi-
cal and Anthropological Sciences 12: 191.
http://doi.org/10.1007/s125210-020-01134-x
Amicone S., Croce E., Castellano L., and Vezzoli G. 2020.
Building Forcello: etruscan wattle-and-daub technique in
the Po plain (Bagnolo San Vito, Manua, Notrhern Italy).
Archaeometry 62–3: 521–537.
https://doi.org/10.1111/arcm.12535
Cultrone G., Rodriguez-Navarro C., Sebastian E., Cazalla
O., and De La Torre M. J. 2001. Carbonate and silicate
phase reactions during ceramic firing. European Journal
of Mineralogy 13: 621–634.
Cuomo di Caprio N. 1985. La ceramica in archeologia.
La ceramica in archeologia: antiche tecniche di lavora-
zione e moderni metodi d’indagine. L’Erma di Bretschnei-
de. Rome. 
Dular J. 1982. Hal∏tatska keramika v Sloveniji. Dela SAZU
23. Slovenska akademija znanosti in umetnosti. Ljubljana.
Dular J., Tecco Hvala S., and Horvat πavel I. 2002. Brona-
stodobno naselje Oloris pri Dolnjem Lako∏u. Opera Insti-
tuti Archaeologici Sloveniae 5. Zalo∫ba ZRC. Ljubljana. 
Gasparini D., Miari M. 2017. Lo scavo del Foro Annonario
di Cesena: indagini di un sito dell età del Bronzo in un
contesto pluristaficato urbano. In F. Rubat Borel, M. Cupi-
tò, C. Delpino, A. Guidi, and M. Miari (eds.), Le età del
Bronzo e del Ferro in Italia: contesti protostorici in sca-
vi urbani. Incontri annuali di preistoria e protostoria.
II Incontro Annuale di Preistoria e Protostoria IAPP. Isti-
tuto italiano di preistoria e protostoria. Firenze: 23–26.
Gerbec T. 2015. Hotinja vas pri Mariboru. Zbirka Arheo-
logija na avtocestah Slovenije 45. Zavod za varstvo kultur-
ne dedi∏≠ine Slovenije. Ljubljana.
Gliozzo E. 2020. Ceramic technology. How to reconstruct
the firing process. Archaeological and Anthropological
Sciences 12: 260.
https://doi.org/10.1007/s12520-020-01133-y
Goldberg P., Macphail R. I. 2006. Practical and theoretical
geoarchaeology. Wiley-Blackwell. Malden, Oxford, Victoria.
Gosselain O. P. 1992. Bonfire of the Enquiries. Pottery
Firing Temperature in Archaeology: What for? Journal of
Archaeological Science 19: 243–259. 
Grahek L. 2015. Orehova vas. Zbirka Arheologija na avto-
cestah Slovenije 46. Zavod za varstvo kulturne dedi∏≠ine
Slovenije. Ljubljana.
Manca Vinazza, Matej Dolenec
402
the future, we will have to pay more attention to the
excavations of such structures, and in the Kras area
there is a lack of scientific research. Only with such
an approach will we be able to understand more
about pottery technological practices in the Early
Iron Age.
However, the non-local origin of the ceramic situla
from πtanjel does not suggest the use of two-chamber
kilns with a perforated floor for the firing of the pot-
tery at the end of the Early Iron Age in the Kras area.
Since the clay for ceramic situla does not originate
from the Eugaeum area, we still need to find a closer
production area for this type of vessel. Some addi-
tional local clay sampling in a broader area close to
key Early Iron Age sites (e.g., Tomaj, Most na So≠i,
Gradisca di Spilimbergo in Italy) thus needs to be
done.
Finally, we would like to point out that the level of
technological knowledge was also determined by the
properties of the raw material available in a certain
area. Thus, the final results must also be under-
stood in light of the natural resources (e.g., clay qua-
lity) of the area and not only in terms of the level
of technological development, as is often the case in
archaeological studies.
The article was written within the Archaeology Re-
search Programme at the Scientific Institute of the
Faculty of Arts of the University of Ljubljana (P6-
0247) and the Geoenvironment and Geomaterials
Programme Group at the Faculty of Natural Sciences
and Engineering (P1-0195), which were co-financed
by the Slovenian Research Agency from the state bud-
get. The authors acknowledge the financial support
from the Slovenian Research Agency (research core
funding No. P6-0247 and P1-0195).
We would like to thank all the students of the Depart-
ment of Archaeology, Faculty of Arts, University of
Ljubljana who helped build the kiln, Paola Koro∏ec
for help during the firing process, and Dr. Jaka Bur-
ja from The Institute of Metals and Technology (IMT)
for firing samples in the electrically operated kiln.
We would also like to thank the company Gori∏ke
opekarne d.o.o. for the donation of the clay. 
ACKNOWLEDGEMENTS
References
∴
Pottery firing in the Early Iron Age in western Slovenia
2018. Naselbinska keramika z Mosta na So≠i/Pottery
from the settlement at Most na So≠i. In J. Dular, S. Tec-
co Hvala (eds.), Ωeleznodobno naselje Most na So≠i.
Razprave/The Iron Age settlement at Most na So≠i.
Treatises. Opera Instituti Archaeologici Sloveniae 34.
Ljubljana: 249–307.
Grahek L., Ko∏ir A. 2018. Analiza naselbinske keramike z
Mosta na So≠i z vrsti≠nim elektronskim mikroskopom/
Scanning electron microscopy analysis of the pottery from
the settlement at Most na So≠i. In J. Dular, S. Tecco Hva-
la (eds.), Ωeleznodobno naselje Most na So≠i. Razprave/
The Iron Age settlement at Most na So≠i. Treatises. Ope-
ra Instituti Archaeologici Sloveniae 34. Ljubljana: 307–321.
Guo M. 2017. Variability in pottery firing technology.
Choice or technical development? Chinese Archaeology
17: 179–186. https://doi.org/10.1515/char-2017-0015
Gu∏tin M., Tiefengraber G., Pavlovi≠ D., and Zorko M.
2017. Nova tabla pri Murski Soboti. Zbirka Arheologija
na avtocestah Slovenije 52/1. Zavod za varstvo kulturne
dedi∏≠ine Slovenije. Ljubljana.
Habi≠ P. 1979. Problematika geografskega vrednotenja
Krasa. Geografski vestnik LI: 147–158.
Hänsel B., Mihovili≤ K., and Ter∫an B. 2015. Monkodonja.
Istra∫ivanja protourbanog naselja bron≠anog doba Is-
tre. Knjiga 1. Iskopavanje i nalazi gra∂evina / Monko-
donja. Forschungen zu einer protourbanen Siedlung
der Bronzezeit Istriens. Teil 1. Die Grabung und der Bau-
befund. Monografije i katalozi/Monographien und Katalo-
ge 25. Arheolo∏ki muzej Istre/Archäologisches Museum Is-
triens. Pula / Pulj. 
Heimann R. B. 1978–1979. Mineralogische Vorgänge
beim Brennen von Keramik und Archäothermometrie.
Acta Praehistorica et Archaeologica 9–10: 79–102. 
Horvat πavel I. 1988–1989. Bronastodobna naselbina
Oloris pri Dolnjem Lako∏u. Arheolo∏ki vestnik 39–40:
127–145.
Iaia C., Moroni Lanfredini A. (eds.). 2019. L’età del ferro
a Sansepolcro. Attività produttive e ambiente nel sito di
Trebbio. Aboca Edizioni. Peruggia.
Jeffra C. D. 2015. Experimental approaches to archaeolo-
gical ceramics: unifying disparate methodologies with the
chaíne opératoire. Archaeological Anthropological Sci-
ence 7: 141–149. 
Josipovi≤ D., Turk M., Rupnik J., Brezigar B., To∏kan B.,
and Kova≠ M. 2015. Kon≠no strokovno poro≠ilo o arheo-
lo∏ki raziskavi ob gradnji. Arheolo∏ko izkopavanje v
Dobravi – Oto≠cu (parc. ∏t. 121, k. o. 1460 πentpeter).
Unpublished archaeological report. Institute for the Pro-
tection of Cultural Heritage of Slovenia, Nova Gorica. Id-
rija. 
Jurkov∏ek B. 2013. Geolo∏ka karta Krasa/Geological
map of Kras (Slovenia). 
Kerman B. 2011. Pod Kotom – sever pri Krogu. Zbirka
Arheologija na avtocestah Slovenije 24. Ljubljana.
2013. Kalinovnjek pri Turni∏≠u. Zbirka Arheologija na
avtocestah Slovenije 33. Ljubljana.
Kovárník J. 1999. Die Technologie der vorgeschichtlichen
Keramik mit Rücksicht auf ihr Brennen. In E. Jerem, I. Po-
roszlai (eds.), Archaeology of the Bronze and Iron Age.
Experimental Archaeology. Archaeolingua. Budapest:
315–327. 
Leghissa E. 2011. Bronastodobna naselbina Medvode –
Svetje. Obdelava arheolo∏kih ostalin in najdb iz izkopa-
vanj 2007. Diploma thesis. University of Ljubljana. Faculty
of Arts. Ljubljana.
Lemonnier P. (ed.). 1993. Technological choices. Trans-
formation in material cultures since the Neolithic. Ma-
terial cultures. Routhledge. London & New York. 
Levi S. T. 2010. Dal coccio al vasaio. Manifattura, tecno-
logia e classificazione della ceramica. Zanichelli. Bo-
logna. 
Lonza B. 1981. La ceramica dei castelliere degli Elleri.
Società per la preistoria e protostora della regione Friuli-
Venezia Giulia, Quaderno n. 4. Edizioni “Italo Svevo”. Tri-
ste.
Macphail R., Goldberg P. 2018. Applied Soils and Micro-
morphology in Archaeology. Cambridge Manuals in ar-
chaeology. Cambridge.
Maggetti M, Neururer C., and Ramseyer D. 2011. Tempe-
rature evolution inside a pot during experimental surface
(bonfire) firing. Applied Clay Science 53(3): 500–508.
https://doi.org/10.1016/j.clay.2010.09.013
Maritan L. 2018. Ceramic material. In C. Nicosia, G. Stopps
(eds.), Archaeological soil and sediment micromorpfo-
logy. John Wiley & Sons. Oxford: 205–212.
Maselli Scotti F. 1978–1981. Primi risultati sullo scavo di
Cattinara ed i castellieri triestino nel’età del ferro. Atti
della Società per la Preistoria e Protostoria della regio-
ne Friuli-Venezia Giulia 4: 281–309.
1983. Le strutture dei castellieri di Monrupino e Rupin-
piccolo. Preistoria del Caput Adriae. Videm: 214–215.
403
Manca Vinazza, Matej Dolenec
Mihovili≤ K. 2020. Zidni glineni dijelovi gra∂evina i opre-
me iz bron≠anodobne gradine Monkodonja. In B. Hän-
sel, K. Mihovili≤, and B. Ter∫an (eds.), Monkodonja. Istra-
∫ivanje protourbanog naselja bron≠anog doba Istre.
Knjiga 3. Nalazi od metala, gline, kosti i kamena te ljud-
skih i ∫ivotinjskih kostiju/Forschungen zu einer proto-
urbanen Siedlung der Bronzezeit Istriens. Teil 3. Die Fun-
de aus Metall, Ton, Knochen und Stein sowie die mensch-
lichen und tierischen Knochen. Pula/Pulj: 13–109.
Mu∏i≠ B. 1999. Geophysical prospecting in Slovenia: an
overview with some observatons related to the natural
environment. Arheolo∏ki vestnik 50: 349–405.
Poggiani Keller R. 1994. L’ultima fase di vita dell’insedia-
mento. Due fornaci per ceramica della media età del fer-
ro. In R. Poggiani Keller (ed.), Il villaggio preistorico e
le fornaci di Ponte S. Marco. Calcinato. Ikonos: 75–89.
Quinn P. S. 2015. Ceramic Petrography. The Interpreta-
tion of Archaeological Pottery & Related Artefacts in
Thin Section. Archaeopress. Oxford.
2022. Thin section Petrography, Geochemistry and
Scanning Electron Microscopy of Archaeological Ce-
ramics. Archaeopress. Oxford. 
https://doi.org/10.32028/9781803272702
Quinn P. S., Benzolli A. 2018. XRD and Materials Analysis.
DOI: 10.1002/9781119188230.saseas0619
Rado P. 1988. An introduction to the technology of pot-
tery. The Institute of ceramics. Pergamon press. Oxford. 
Rapi M., Quirino T., Castellano L., + 3 authors, and Bus-
nelli S. 2019. Per scalfare, per cuocere e per produrre. Le
strutture da fuoco dell’abitato etrusco del Forcello di Bag-
nolo S. Vito: aspetti tipologici e funzionali. In A. Peinetti,
M. Cattani, and F. Debandi (eds.), Focolari, forni e forna-
ci tra neolitico ed età del ferro. Comprendere le attivi-
tà domestiche e artigianali attraverso lo studio delle in-
stallazioni pirotechnologiche e dei residui di combus-
tione. Sesto incontro annuale di preistoria e protostoria.
Università di Bologna. Bologna: 107–109.
Rice P. 1987 (2005). Pottery analysis. A sourcebook. The
University of Chicago Press. Chicago, London. 
Rokavec D. 2014. Gline v Sloveniji. Geolo∏ki zavod Slove-
nije. Ljubljana. 
Roux V. 2016. Ceramic Manufacture: The chaîne opérato-
ire Approach. In A. Hunt (ed.), The Oxford Handbook of
Archaeological Ceramic Analysis. Oxford University Press.
Oxford: 101–117. 
Rye O. S. 1981. Pottery technology. Principles and re-
construction. Taraxacum. Washington, D.C.
Saracino M. 2014. Dalla terra al fuoco. La tecnologia ce-
ramica degli antichi Veneti. Scienze e Lettere. Roma.
Shoval S. 2016. FTIR in Archaeological Ceramic Analysis.
In A. Hunt (ed.), The Oxford Handbook of Archaeologi-
cal Ceramic Analysis. Oxford University Press. Oxford:
509–530. 
πavel I., Sankovi≠ S. 2013. Nedelica pri Turni∏≠u. Zbirka
Arheologija na avtocestah Slovenije 39. Zavod za varstvo
kulturne dedi∏≠ine Slovenije. Ljubljana.
Thér R. 2014. Identification of pottery firing structures
using the thermal characteristics of firing. Archaeometry
56: 78–99. https://doi.org/10.1111/arcm.12052
Thér R., Kallistová A., Svoboda Z., +3 authors, and Bajer
A. 2018. How was Neolithic Pottery fired? An Exploration
of the Effects of Firing Dynamics on Ceramic Products.
Journal of Archaeological Methodology and Theory 26:
1143–1175. https://doi.org/10.1007/s10816-018-9407-x
Tomani≠ Jevremov M., Gu∏tin M. 1996. Keltska lon≠arska
pe≠ s Spodnje Hajdine pri Ptuju. Arheolo∏ki vestnik 47:
267–278.
Udov≠ K., Vinazza M. 2015. Rimski lon≠arski obrat na
Otoku pri Metliki. In M. Jane∫i≠, B. Nadbath, T. Mulh, and
I. Ωi∫ek (eds.), Nova odkritja med Alpami in ∞rnim mor-
jem: rezultati raziskav rimskodobnih najdi∏≠ v obdobju
med leti 2005 in 2015. In memoriam Iva Mikl Curk. Za-
vod za varstvo kulturne dedi∏≠ine Slovenije. Center za
preventivno arheologijo. Pokrajinski muzej Ptuj Ormo∫.
Ljubljana, Ptuj: 143–158.
Vinazza M. 2011. Prazgodovinski πtanjel na Krasu. Izko-
pavanja 2010. Diploma thesis. University of Ljubljana. Fa-
culty of Arts. Ljubljana.
2016. Silosi – posebne kerami≠ne oblike: prispevek k
poznavanju gospodinjstev v starej∏i ∫elezni dobi na Kra-
su/Silos – special ceramic forms: contribution to the
knowledge of the Early Iron households in the Karst
region. Arheo 33: 7–23.
2021. Naselbinska keramika starej∏e ∫elezne dobe na
Krasu/Settlement pottery from the Early Iron Age in
Kras. Arheolo∏ki vestnik 72: 419–452.
https://doi.org/10.3986/AV.72.14
Ωibrat Ga∏pari≠ A., Horvat M., and Mirti≠ B. 2014. Ceramic
petrography, mineralogy and typology of Eneolithic pot-
tery from Kra∏nja, Slovenia. Documenta Praehistorica
41: 225–236. https://doi.org/10.4312/dp.41.12
404
Pottery firing in the Early Iron Age in western Slovenia
405
3. A thin section of a vessel fired in a kiln at 670°C.
8x magnification Leica Stereomicroscope EZ4.
4. A thin section of Sample 2. XPL with Zeiss Axio-
cam 305 color.
5. Ren≠e clay, fired at 600°C, Sample 6. 8x magni-
fication Leica Stereomicroscope EZ4.
6. Ren≠e clay, fired at 800°C, Sample 7. 8x magni-
fication Leica Stereomicroscope EZ4.
7. πtanjel, Samples 9 (outer surface), 10 (fracture),
11 (inner surface). 8x magnification with Leica
Stereomicroscope EZ4.
8. Ren≠e clay with admixed calcite, Sample 12. 8x
magnification Leica Stereomicroscope EZ4.
1. πtanjel, red slip coating on the situla, outer sur-
face. 8x magnification Leica Stereomicroscope EZ4.
2. πtanjel, coating thin section, a fracture (orange
colour). 40x magnification. PPL with Zeiss Axio-
cam 305 color.
Appendix