JOURNAL OF RAMAN SPECTROSCOPY
J. Raman Spectrosc. 2001; 32: 17–22
Raman spectroscopic study of 3000-year-old human
skeletal remains from a sambaqui, Santa Catarina,
Brazil
H. G. M. Edwards,1 * D. W. Farwell,1 D. L. A. de Faria,2 A. M. F. Monteiro,2 M. C. Afonso,3
P. De Blasis3 and S. Eggers4
1
2
3
4
Department of Chemical and Forensic Sciences, University of Bradford, Bradford BD7 1DP, UK
Instituto de Quimica, Universidade de São Paulo, Av. Professor Lineu Prestes 748, C.P. 26077, 05513-970 São Paulo, SP, Brazil
Museu de Arqueologia e Etnologia, Universidade de São Paulo, Av. Prof. Almeida Prado 1466, 05508-900 São Paulo, SP, Brazil
Instituto de Biociencias, Universidade de São Paulo, C.P. 11461, 05508-900 São Paulo, SP, Brazil
Received 24 July 2000; Accepted 3 September 2000
A Raman spectroscopic study of red-pigmented human bones from a 3000-year-old sambaqui burial
was undertaken for the first time. Visible (633 nm) and near-infrared (1064 nm) excitation were used to
characterize the pigment and its substrate; the red pigment is haematite, iron(III) oxide, which proved to
be of a pure form and for which no previous heat treatment processing had been adopted. There is clear
evidence in heavily pigmented areas of a ‘limewash’ layer which had been applied to the body of the
deceased prior to treatment with ochre. Comparisons made with previous Raman studies of archaeological
bone from a separate excavation indicate that mineralization of the present specimens is well advanced,
with evidence of calcium carbonate incorporation into the hydroxyapatite phosphatic matrix. Copyright 
2001 John Wiley & Sons, Ltd.
INTRODUCTION
The application of Raman spectroscopic techniques to archaeological materials has been undertaken only recently.1 The
conservation of specimens and artefacts from archaeological
excavations and in museum collections requires knowledge
of the chemistry of decay processes and of materials which
have been used in previous restorative work; some examples
of this are provided by the discoloration of ancient dyed textiles and the crumbling of mummified or desiccated human
tissues. In this, the effects of external parameters such as
the incident light intensity, exposure levels of UV radiation, humidity and temperature changes even in museum
galleries have yet to be fully understood and the situation
is complicated even further by reaction of the specimen
with previously applied preservatives or exogenous chemicals. In earlier studies, we applied Raman spectroscopy to
the characterization of degraded photographic prints2 and
linens from archaeological excavations.3 The use of impure
materials of imprecise formulation in the original production of materials and artefacts provides a fascinating insight
Ł Correspondence to: H. G. M. Edwards, Department of Chemical and
Forensic Sciences, University of Bradford, Bradford BD7 1DP, UK;
e-mail: [email protected]
Contract/grant sponsor: British Council
Contract/grant sponsor: CAPES
into ancient technologies but can also give rise to problems
in conservation through chemical reaction in substrates; an
example of this which has been recently studied by Raman
spectroscopy is the blackening of a lead-white pigment in a
mediaeval manuscript through interaction of the lead with
sulfide in an egg-white binder.4
The non-destructive analytical capability of Raman
spectroscopic techniques for rare and valuable specimens,
in conjunction with the ease of specimen mounting for
which little or no chemical or mechanical pretreatment
are necessary, has resulted in the recent adoption1 of
the technique for archaeological scientific work. Novel
spectroscopic information has been forthcoming in the
characterization of specimens as diverse as pigments,
corrosion products and biomaterials such as ivories, resins,
waxes, skin and bone. The non-destructive characterization
of minute quantities of material using Raman microscopy
has been applied successfully to a wide range of specimen
sizes from single paint particles to large canvasses; in our
laboratories, we have analysed particles of paint fragments
from mediaeval frescoes of about 1 µg, and have also
examined elephant ivory tusks weighing about 3 kg. This
large range of specimen quantitation is particularly well
suited to archaeological and museum sciences.
A major advantage of analytical Raman spectroscopy in
the archaeological context is the ability to identify inorganic
Copyright  2001 John Wiley & Sons, Ltd.
18
H. G. M. Edwards et al.
and organic molecules and molecular ions in the same
wavenumber range scan; hence mineral pigments and biomaterials can be characterized and their interactions examined. Several important scenarios have been investigated
along these lines, including pigment-binder identifications
in manuscripts and wall paintings5,6 and the identification
of the onset of a biogeological degradation in mediaeval
frescoes and prehistoric rock art caused by lichen or fungal
attack on plaster or rock substrata.7 – 9
In this paper, we report for the first time a Raman
spectroscopic study of pigmented human skeletal remains
from the excavation of a 3000-year-old skeleton. Much has
been written about the use of red ochre in prehistoric cultures
for decoration and its symbolism in funerary rites.10,11 The
role of red ochre, in particular, is believed to be especially
important because of the widespread occurrence of this
pigment in early burials, dating back some 500 000 years
to Homo erectus at Olduvai Gorge,12 where two pieces
of red ochre were found buried alongside the skeletal
remains. At Ambrona and Terra Amata, about 75 pieces
of ochre, with colours ranging from yellow to red–brown,
were excavated and one large piece showed evidence of
early trimming and working.13,14 Clearly, the meaning and
symbolism of the red ochre colour was important to our
ancestors, and it could well have symbolic association with
life and blood (c.f. Greek haematite, Fe2 O3 ).15,16 Because of
the controversies which are enduring about the symbolism
of the red colour in ancient cultures and the possible
reasons for body painting in funerary rites and practices,
the chemical significance of ochre identification has not been
addressed hitherto. In earlier studies, we examined ochres
from several prehistoric and mediaeval cave paintings and
frescoes and have assembled a database of characteristic
Raman bands17 – 20 which can be used to identify minerals
such as haematite, magnetite, lepidocrocite and goethite,
all of which belong to the iron oxide–hydroxide system
and which are inter-related as shown in Fig. 1 and Table 1.
The identification of a particular pigment or mixtures
can provide some novel information about the ancient
technologies used by prehistoric cave artists and later
painters.21,22 In the present work, there is a real opportunity
to apply Raman spectroscopic techniques to the analysis
of red ochre-stained archaic human bones and to analyse
the spectra using our databases of mineral pigments and
biomaterials. In this way, we hope to answer the following
questions:
ž Is there evidence for an ancient technology of red ochre
preparation for body painting?
ž Was any binding agent, organic or inorganic, used to apply
the pigment to the body?
ž Can the presence of biodeteriorative chemicals caused
by the reaction of tissue degradation materials and the
pigment be observed?
Copyright  2001 John Wiley & Sons, Ltd.
β
γ
α
α
γ
Figure 1. Mineral pigments in the iron(III) oxide/hydroxide
system.
EXPERIMENTAL
Samples
In the South of Santa Catarina State, Brazil, is a concentration of 31 sambaquis, which are being investigated
by the Camacho Archaeological Project. A sambaqui is
the name given to the archaeological evidence left by
fisher/hunter/gatherer groups who inhabited the Brazilian coastline about 3000–5000 years ago.23 A sambaqui is a
large mound (Plate 1) formed of mostly shells and fish bones,
which contains human remains and lithic artefacts, hearths
and habitation structures, which may be up to about 100 m in
height. Archaeologists are endeavouring to place sambaquis
in the context of a settlement system and to understand the
process of sambaqui formation.21
The Jaboticabeira II sambaqui, which provided the
samples studied here, is one of the most important in the
Santa Catarina State and, owing to the number of burials
found within, it is believed that a major function was related
to funerary practices.22
Several bones were excavated from the Jaboticabeira II
sambaqui, representing a left humerus, left ulna, left radius,
fragment of a left illium, fragment of a right scapula, fragment
of a left fibula and two falanges, constituting burial No. 32
at Locus 2.16, trench 15. The bones were found associated
with fish vertebrae and many sea-shells and were those of
a young adult of indeterminate sex; the remains exhibited
a slight periostisis on the fibula and scapula and a nonfatal systemic infection. Almost all of the bones and bone
fragments exhibited pronounced ochre coloration and marks,
J. Raman Spectrosc. 2001; 32: 17–22
Raman spectroscopy of ancient human bones
Table 1. Iron oxide minerals providing a Raman spectroscopic database;a other materials found in association are included for
information
Mineral
Chemical formulation
Pigment colour
Haematite
Goethite
Lepidocrocite
Magnetite
Pyrolusite
Quartz
Calcite
Gypsum
Anhydrite
Rutile
Anatase
Whewellite
Weddellite
Lampblack/soot
Bone black
˛-Fe2 O3
˛-FeO(OH)
-FeO(OH)
Fe3 O4
ˇ-MnO2
˛-SiO2
CaCO3
CaSO4 Ð2H2 O
CaSO4
TiO2
TiO2
CaC2 O4 ÐH2 O
CaC2 O4 Ð2H2 O
C
C
Red
Red–brown
Red–yellow
Black
Black
Colourless
White
White
White
White
White
White
White
Black
Black
a
Characteristic Raman wavenumber/cm
1
225 s, 247 w, 299 s, 412 m, 498 w, 613 w
243 w, 299 m, 385 s, 479 w, 550 w, 685 vw, 993 vw
245 s, 373 m, 493 sh, 522 w, 650 sh, 719 w
302 w, 533 w, 663 s
620 m, 640 mw
148, 357 w, 465 s
154 s, 282 m, 712 m, 1086 s
140 m, 181 m, 493 m, 619 m, 679 m, 1007 s, 1132 m
124 m, 415, 496, 674 mw 1015 s, 1127, 1160 m
147 s, 242 s, 440 s, 611 s
144 s, 201 s, 397 s, 512 s, 634 s
1496 s, 1464 s, 906 m, 506 m
1472 s, 900 m, 502 m
1590 m, 1360 m
1590 m, 1360 m, 1070 w, 964 s, 670 mw
Haematite, goethite, lepidocrocite and magnetite, all with 633 nm excitation; all others 1064 nm excitation.
which were particularly thickly layered on the humerus. All
specimens were in a fragile and friable condition.
For our Raman spectroscopic work, particular attention
was paid to this heavily coloured humerus specimen, where
in places the pigment could be seen lying on the surface of
an indefinite mass which was attached to the bone.
Databases of iron oxide–hydroxide minerals17,20 (specimens obtained from the Natural History Museum Collections, London) and skeletal material of bone and related
materials (ivory, teeth) have also been compiled for comparison purposes (H. G. M. Edwards, S. O’Connor, R. H. Brody,
A. M. Pollard and D. W. F. Farwell, to be published). Several
specimens which have been analysed using these databases
were obtained from archaeological contexts, including
human bone (Roman, Romano-British, Viking and mediaeval), hair (mediaeval), teeth (Roman and mediaeval), nail
(mediaeval) and skin (Neolithic and mediaeval).
Although it is easy to find information about the presence
of ochre in burials located in sambaquis in the archaeological
literature, this material has actually never been analysed to
date. The archaeologists have identified the ochre form, if it
appears in pebbles or powder deposits, where it was found
(on the whole body, near the skull, etc.), and the colour
(bright red, red–yellowish). However, archaeological ochre
analysis hitherto has been restricted to the pigments used in
rock art.
Raman spectroscopy
Raman spectra were obtained in the near-infrared region
(1064 nm) using a Bruker IFS66 instrument with an FRA
106 Raman module attachment and a dedicated Raman
microscope. In the macroscopic mode, spectra could be
obtained with 1000 scans of data accumulation over the
Copyright  2001 John Wiley & Sons, Ltd.
wavenumber range 50–3500 cm 1 at 4 cm 1 resolution from
samples with a ‘footprint’ or spot size of 100 µm. In the
microscopic mode, this ‘footprint’ is reduced to about 8 µm
using a ð100 magnification objective lens.
In the visible region, excitation at 632.8 nm (Spectra
Physics He–Ne laser) with a Renishaw Raman system
(fitted with an Olympus metallurgical microscope) were
recorded in the extended mode over the wavenumber range
100–1800 cm 1 . The samples were studied on a microscope
slide and no previous preparation was required. The laser
was focused to a 1–2 µm spot by a ð80 lens and the
laser power was kept as low as possible to avoid thermal
degradation. As found to be typical for archaeological
biomaterials, the bone samples fluoresced and this swamped
the Raman signals.
RESULTS AND DISCUSSION
Figure 2 shows a stack-plot of the Raman spectra over the
wavenumber range 100–1200 cm 1 of a heavily pigmented
region of bone, the bone itself and two specimens of the
iron oxide–hydroxide pigment system in Fig. 1, namely
haematite (˛-Fe2 O3 ) and goethite (˛-FeOÐOH).
The heavily pigmented area of the bone shows bands
at 244, 292, 409 and 610 cm 1 , which are characteristic of
haematite20,24 (Table 1). This spectrum is interesting because
it confirms that the pigment is, in fact, haematite, and
provides a clear indication for the first time of the generic
term ‘red ochre’ used by archaeologists to describe this
pigmentation. It has long been realized that red ochre
formulations varied in ancient times and that this usually
included fine sand or clays; an example of ‘red ochre’ is given
in the Fourier transform (FT) Raman spectral stack-plot in
J. Raman Spectrosc. 2001; 32: 17–22
19
20
H. G. M. Edwards et al.
Figure 2. FT-Raman stack-plot of pigments in the
wavenumber range 150–850 cm 1 ; from top, (a) heavilypigmented specimen of 3000-year-old skeletal bone; (b) red
ochre standard; (c) goethite; (d) haematite; (e) lepidocrocite;
(f) magnetite. The four bands characteristic of haematite at
244, 292, 409 and 610 cm 1 are clearly present in the
pigmented bone specimen, spectrum a.
Fig. 2. The presence of quartz is clearly indicated by the band
at 465 cm 1 and the larger bandwidths of the (FeO) and υ
(FeO) vibrations can be recognized.
The spectrum in Fig. 3 shows a mediaeval sample of
pigment from the finest example of English wall painting
from this period, the ‘Entombment of Christ’ at Winchester
Cathedral which was executed in c.a. 1175 AD here, the
presence of a sharp Raman band at 465 cm 1 from ˛quartz (sand particles) is clearly seen in the propietary red
ochre, which is absent from the mediaeval specimen.24 In
mediaeval documentation it was stated that artists often
used fine river sand to assist in the pulverization of their
pigments for the finest quality work. However, the spectral
bands in the pigmented bone specimens studied here are
assignable to haematite alone—there is no trace of goethite
or simple processing of materials by heat having being
undertaken (Fig. 2); other examples of early ochre studied
in our laboratories have shown the presence of carbon or
manganese(IV) oxide in admixture to produce a deep, rich
colour.18,19 Comparison of the ‘red ochre’ spectrum with
that of the non-pigmented area of bone nearby (see later)
shows that the phosphate modes in the latter, characterized
by the sharp (PO) symmetrical stretching mode at 960 cm 1
and weaker υ(PO4 ) modes near 450 and 600 cm 1 , do not
occur in the pigmented specimen spectrum; hence, it may
be concluded that the pigmented layer is thick enough to
prevent penetration of the laser beam to the bone substratum.
Analysis of the FT-Raman spectrum of the unpigmented
area of the bone also shows that almost complete leaching out
of the organic component (mainly collagen) has occurred. A
comparison of the bone spectrum from the 3000-year-old
skeleton and from a Roman bone specimen25 in Fig. 4
shows how there has been extensive mineralization of the
sambaqui specimen; the proteinaceous (CONH), υ(NH) and
υ(CH2 ) modes of collagen at 1650, 1450 and 1230 cm 1 in
Copyright  2001 John Wiley & Sons, Ltd.
Figure 3. FT-Raman stack-plot of red pigments from the
mediaeval wall painting (c.a. 1175 AD) in the Chapel of the Holy
Sepulchre in Winchester Cathedral, U.K. (a) Red pigment
specimen from wall painting; (b) specimen of pure cinnabar
(vermilion), mercury(II) sulfide; (c) specimen of proprietary red
ochre standard (haematite C clay C sand). The presence of
both cinnabar and red ochre in the adulterated pigment can be
seen. The broad, strong feature centered at about 780 cm 1 is
ascribed to a ‘limewash,’ calcium oxide–hydroxide, which with
powdered calcite (1086, 712 cm 1 ) was used in the
preparation of the surface for painting. A broad band ascribed
to this ‘limewash’ is seen in the top spectrum of Fig. 2.
younger bone have been considerably reduced in intensity
for the ancient specimen. Also, in the 3000-year-old sample
the presence of carbonate (weak intensity peaks at 1086,
712 and 283 cm 1 ) can be seen, obscured somewhat by
the hydroxyapatite modes near 1000 cm 1 , which indicates
mineralization of this specimen through absorption of
carbonaceous material into the inorganic matrix on vacation
of the sites occupied by the collagenic component. Clearly,
the extent of mineralization here is much greater than that
observed with the c.a. 2000-year-old Raman bone specimen
shown in Fig. 4. It should be noted that visible excitation of
the Raman spectrum of bone was accompanied by extensive
fluorescence ; this is not unexpected and highlights the need
for both visible and near-IR excitation for recording the
Raman spectra of pigmented biomaterials.
A region of special interest on the humerus bone from
the same skeletal burial was also studied; here, a deeply
pigmented area seems to be overlying what appeared to
be an amorphous mass microscopically. This could be
detritus from the grave site, but we felt that it could be an
important area for more detailed examination since the ochre
is firmly adhered to the paler amorphous mass, which itself
is adherent to the bone. No Raman signals were obtained of
the amorphous material indicative of an organic origin, so we
can conclude that it is not degraded proteinaceous material.
The presence of only a weak (PO) band from phosphatic
bone and absence of (SiO) indicates that it is, likewise,
not a phosphatic or sandy deposit. However, a new broader
feature appeared in the form of an ill-resolved doublet at 790,
J. Raman Spectrosc. 2001; 32: 17–22
Raman spectroscopy of ancient human bones
Plate 1. The Jaboticabeira II sambaqui which provided the ‘ochred bone’ samples for the current study.
Copyright  2001 John Wiley & Sons, Ltd.
J. Raman Spectrosc. 2001; 32
Raman spectroscopy of ancient human bones
Figure 4. FT-Raman stack plot in the wavenumber range
150–1800 cm 1 of (a) modern skeletal bone; (b) bone die from
Roman villa excavation at Frocester, UK, c.a. 200 AD and
(c) unpigmented bone from 3000-year-old sambaqui skeletal
remains. The very weak band intensity of the proteinaceous
bands in the lower spectrum (c) indicates that extensive
removal or degeneration of collagen has occurred in the
human sambaqui skeleton compared with the 1800-year-old
Roman bone specimen.
710 cm 1 . In another project (H. G. M. Edwards and F. Rull
Perez, to be published), we have been investigating the
spectra of ancient rendering for wall paintings; an identical
match is found for the ubiquitous ‘limewash’ or slaked lime
that was much in vogue in ancient cultures as a binding
and sizing agent for the preparation of surfaces to aid
adhesion of pigments. It was much refined as a practice
by the Romans,25 and a stack-plot of a 2000-year-old Roman
pigment from a wall-painting fragment is shown in Fig. 5, in
which the limewash/calcite preparation is clearly evident.
Examination of a ‘paler’ region of bone which was devoid of
pigment also revealed this characteristic limewash feature,
and this is shown in the stack-plot in Fig. 6. Clearly, it
seems to have been the practice in this later archaic culture
to have prepared the body with ‘limewash,’ upon which
the red ochre was then applied. It would be important
archaeologically to study the artefacts and habitation of this
culture to see if there is evidence of an ancient technology
associated with lime production. An important conclusion
from Fig. 6 is the presence of limewash on the outer surface
of the bone only and its absence elsewhere. The absence of
calcite from the spectrum of the lime-washed bone is also
significant in that it indicates that the lime layer has been
protected from attack by moist, damp, atmospheric carbon
dioxide; we can therefore conclude that the thickly applied
pigment has been material in this, as conditions elsewhere in
the sambaqui are damp.
CONCLUSIONS
The first Raman spectroscopic study of pigmented 3000-yearold human skeletal remains has demonstrated successfully
Copyright  2001 John Wiley & Sons, Ltd.
Figure 5. FT-Raman stack-plot in the wavenumber range
50–1500 cm 1 of (a) red pigmented specimen (cinnabar) from
King Herod’s palace at Jericho, Israel, (b) the substratum
devoid of pigment and (c) cinnabar. The presence of the
‘limewash’ and calcite peaks at 780 (broad), 1086, 712, 280
and 180 cm 1 should be noted in (a) and (b) for comparison
with Fig. 6.
Figure 6. FT-Raman stack-plot in the wavenumber range
350–1250 cm 1 of (a) a prepared substratum from King
Herod’s villa at Jericho, showing the ‘limewash’ and calcite
signatures, (b) upper surface of 3000-year-old skeletal bone
containing ochre pigment and (c) lower surface of
3000-year-old skeletal bone devoid of pigment. The absence
of ‘limewash’ bands in the lower spectrum (c) clearly indicates
that this material is closely associated with the applied
pigmentation and has not been incorporated into the bone
from the surrounding burial environment.
the applicability of the technique and has provided novel
information for further archaeological evaluation. In particular, we note the purity of the red haematite used and that
its application did not depend on the addition of clays or
fine sand as did mediaeval illuminators and artists in wall
paintings and historic manuscripts. Also, it appears that the
pigment was applied over a layer of ‘limewash’ applied
to the body of the deceased; this indicates that an ancient
technology of lime production from calcite, especially seashells used for the site formation, was known to this culture.
J. Raman Spectrosc. 2001; 32: 17–22
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H. G. M. Edwards et al.
Sea-shells contain a form of calcium carbonate known as
aragonite, which on heating to temperatures of about 750 ° C
breaks down into lime, calcium oxide. In ancient cultures, this
lime was powdered and mixed with water to a stiff, creamy,
putty-like consistency which could then be applied to surfaces; its sealing and adhesive properties were well known.24
Hearths and lithic artefacts have been found in the sambaquis
and it is reasonable to propose that these could have fulfilled
several functions in addition to heating and cooking, one of
which was the production of lime from the plentiful supply
of aragonite in close proximity at accessible temperatures.
Acknowledgements
Dalva L. A. de Faria and Howell G. M. Edwards are grateful to the
British Council and to CAPES (Brazil) for Chem Link 2000 project
support during which this investigation was carried out. We are
also appreciative of the support given by colleagues in the Camacho
Archaeological Project.
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