www.excavatedartauthenticity.com       last update: 25/07/2013


Fond. Gottfried Matthaes

Determining the authenticity of excavated art objects
A section of the Museo d�Arte e Scienza






Excavated vases from Greece and Italy
Excavated Bronzes

Excavated Mediterranean glass

Archaeological ceramics from China and America



In the 1990s, The Art Collector�s Museum of Milan (now Museo d�Arte e Scienza) was donated about 1,000 excavated artefacts belonging to the important collections of the Kurau-Matthaes Foundation. These archaeological finds comprise terracotta vases and sculptures, which after about 30 years of research and analysis have proved to be authentic. A part of these objects, together with a number of fake items, have been put on display in room 8 and in other rooms of the Museum�s exhibits for didactic purposes.
By a decree of the Italian Ministry of Culture in 1997, this collection was declared to be of extraordinary art historical interest. Excavated objects of the most important cultures can be observed with magnifying glasses and examined in special test stations in the above rooms.








Acknowledged value
of the Museum�s scientific laboratory and its methods
for determining authenticity


Attitudes towards and use of scientific methods are influenced by local laws and customs.

Basis of judgment: the situation in Italy (where the Museum is located)

The prime institution for the fight against forgery and imitations is the Guardia di Finanza or Financial Police. The most recent catalogue on the determination of authenticity in art, published by the same in June 2007, contains an exclusive six-page presentation of the scientific laboratory of the Museo d�Arte e Scienza in which its methods for dating paintings, furniture, and objects in ivory and other materials are illustrated in detail and their validity, in effect, endorsed.

Judicial proceedings. The probatory value of the spectroscopic dating method is crucial to the outcome of civil and penal judgments involving the determination of the actual age of art works.

The art market: the percentage of inauthentic art works currently on the market is very high. As a consequence a section of the trade rejects scientific methods out of economic necessity. Furthermore, when dating tests give negative results, dealers often tend to maintain that it is not the art work that is at fault but the scientific test result, or that the method is unknown!!

Art lovers and investors. Copies and fakes will continue to be offered as originals as long as buyers of art refuse to follow the same line of conduct adopted when acquiring other �products�, that is to say insisting on a dependable guarantee of the object�s authenticity as the condition for its purchase. It is senseless to content oneself with the personal opinions of experts alone in this age of technology and science. The art market will become trustworthy only when the art lover becomes a connoisseur and, as envisaged by the law, demands a valid certificate.










The following indications are only examples.

Ample information is available in the 3rd volume of our Handbook, illustrated in the last pages of this website.

The visual ascertainment of archaeological provenance.
Excavated ceramics from Greece and Italy



Most of the tests that can be carried out to distinguish archaeological pieces from recent copies are surprisingly simple and accessible also to the layman.

Ceramic articles have been preserved only because they were protected by the earth in which they were buried for centuries. The humidity in the soil, rich in minerals and plant roots, penetrates the ceramic body. These extensive traces left by the earth offer the surest and simplest means of establishing authenticity.

The first test should therefore consist of moistening a clean part of the surface with a wet finger or brush (1). If the object is authentic it will give off a smell similar to that of warm earth after a summer rain.

Petrified traces of roots offer a further clue (2). The roots which cling to the porous ceramic body leave their minerals behind in the form of crystalline deposits on the surface. A natural encrustation can be discerned by the semicircular petrified root bed (drawing a) left by the decomposed root.

Through a normal 10X magnifying glass, which every antique buyer should have with him, these round beds are clearly distinguishable. Forgers try to imitate these marks with applications made of glue, earth and cement on the surface.

Encrustations, if authentic, are sufficient proof that an archaeological item is authentic. Chemically speaking, these crystals are mostly calcium carbonate (CaCO3), a compound of calcium and carbonic acid. A very simple test  demonstrates the authenticity of encrustations: it is sufficient to sprinkle a few drops of hydrochloric acid, a substance to be found in many households. First the surface forms blisters which continue until the material dissolves completely. Unequivocal evidence is provided by a spectroscopic analysis of the encrustations, which a well-equipped laboratory can carry out in a few minutes.


When lit at a certain angle, black-lacquered surfaces nearly always present a film with a metal-blue sheen, which develops over the centuries thanks to catalytic processes in the damp earth (3). The encrustations caused by roots prevent the formation of the blue film, so that after cleaning with hydrochloric acid there remains the shadow of the reticulum of roots to indicate the object�s sure authenticity (3). The absence of this blue sheen on black lacquer should arouse suspicion.



An absolutely certain indication of authenticity is provided by carbonized mould fungi, which develop on edible burial gifts. These fungi expand radially in an irregular way (4). In the course of centuries a micro-organism (Micrococcus carbo) converts the fungus material into carbon. Under a magnifying glass they appear as a crystalline mass, whilst the black stains forgers like to make by spraying black paint on the surface show up as round, smooth-surfaced spots. There is no point in spraying a genuine item with industrial paint: the presence of artificial marks alone is therefore enough to classify the object as a fake.






A further testimony to authenticity is provided by the inside of a vessel which remained for a long time full of water or mud underground. The various levels reached by the water have left rings (5). The inside of faked vases are generally rinsed with a uniform brown or grey mixture of earth and cement or glue which assumes a uniform colour and structure on drying (6).


Not all authentic archaeological finds bear readily visible signs of age. The dry ground of South America, southern Italy and China may produce encrustations which can only be detected with a good microscope.
Antique objects found at the bottom of the sea are not covered in earth crystals but only in the fossil remains of marine animals which are not fakable.




Almost all terracotta vases are found as potsherds in excavations.

The edges of old cracks in excavated pottery have been smoothed by time and corrosion (7). Sharp-edged cracks point to recent damage and therefore a fake object (8).





Fake excavated pottery and 19th century copies thereof also give themselves away because the objects are often bigger and more beautiful than the originals.

Typical of a fake is this urn of a handsome young Etruscan, whose vigorous and healthy appearance is an idealized representation. (9)



Particularly big, beautifully decorated glass objects in a perfect state of preservation are suspect. They were used only rarely in graves. Simple bottles, on the other hand were mass-produced in industrially organized workshops and placed in thousands in tombs.

The ablest copyists of antique glass today are in the Middle East, particularly in Israel, Syria and Jordan. But these fakers do not have the time to meticulously imitate the signs of age produced by wear, corrosion and deposits which, if examined by an expert, will always reveal their true nature.










Excavated Chinese pottery

Much of the inhabited area of China is covered in porous loess, which produces scant mineral deposits on the pottery surface. Nevertheless authentic figures generally have characteristics which, if examined at least under a microscope, can permit a reliable distinction between recent and antique items.

In the fertile loess live many insects and worms which leave petrified traces. (10 - 12)

Visible traces of earth, not noticeable on the painted and glazed areas, must instead be expected in the unprotected areas of the porous ceramic surface, such as on the face and in the interior of a figure (11).





Much appreciated are figures of horsemen (13) and about 80 percent of all those objects declared authentic are fakes. But also for authentic objects most of them are made up of potsherds which have been reassembled and overpainted.




In general, excavated objects from all parts of the world present the same characteristics which can be recognized and interpreted in the same way as indicated for Mediterranean excavated pottery and the best evidence is provided by petrified traces of roots.







Excavated pottery from Central and South America
Pre-Columbian pottery






The ceramics of a number of ancient cultures were painted in smooth, bright colours and patterns conforming to European tastes. Modern acrylic paints used on recent copies tend to achieve a similar optical effect to the genuine colours.
But if a small inconspicuous area is heated with a hot-air gun or over a gas flame the difference is quickly noted: at 300� acrylic colours blister or darken.
Acrylic colours dissolve slowly in alcohol. If a piece of cotton wool soaked in alcohol is left in contact with the paint for an hour, it will wrinkle and can be wiped off (14).

The presence of petrified roots as well as other crystalline deposits on the surface is similar to those on European excavated objects.



Excavated antique glass



Glass wares served as receptacles for food and drink to be consumed in the next life. The carbonized remains of these organic substances are generally visible through the transparent parts of the glass (15).

These marks, which range in colour from brown to black, are a good indication of authenticity. The distribution of the marks is important however, as their position must correspond to the upright or horizontal position in which the container was found in the tomb.

Pottery, and terracotta in particular, are porous materials which absorb large quantities of mineral-rich groundwater. Glass, on the other hand, has an impermeable surface which minerals can penetrate only slowly and in small quantities, forming thin layers.

An absolutely reliable and inimitable characteristic of an authentic encrustation on glass is that over time, at the slightest vibration, paper-thin flakes fall away, accumulating at the bottom of the receptacle (16).



Iridescent antique glass surfaces are particularly prized (17). A favourite way of imitating iridescence on glass is to use gelatin made from bones or fish scales, into which an iridescent powder has been mixed. This is dissolved by a drop of hot water








Excavated bronzes


Few of the antique Greek and Italian bronzes selling on the antiques market are genuine.

It is relatively easy to tell authentic items from fakes as long as the original patina and corrosion of the metal are still in place. It is therefore safe to say that all bronzes more than about one thousand years old which are intact have come down to us because they were buried in the earth, thus acquiring characteristic signs which cannot be faked.(18)


Only in exceptional cases has thin sheet remained preserved for so long. In Figure 19, next to the Etruscan fibula, we can see the lid of a container, the edges of which are so thin that they have been dissolved by the acids present in the earth.

(20) An artificial patina will have been produced by dipping the object into a chemical bath or coloured paint. In both cases only a thin, monochromatic coating is obtained which, once removed, reveals the bare, corrosion-free metal (20).
(21) Modern forgers are skilled in reproducing patinas which at first sight look convincingly genuine (21-22).




The Museum laboratory at the service of art 


The Museum laboratory�s mission is to improve existing scientific methods and elaborate new methods for the ascertainment of the authenticity of art objects. The laboratory�s instruments and know-how for determining authenticity are at the disposal of collectors, art experts, restorers, art galleries and museums. (The staff of the laboratory, who speak the main European languages, are at your disposal for any explanations).

Any excavated object made of ceramic or metal has remained for hundreds of years in close contact with the damp earth. Earth contains acids and dissolved minerals which attack the objects�s surface, forming characteristic and unfakable crystalline encrustations. The presence of these crystals can be easily and accurately observed in the spectroscopic curves and is clearly identified by experts.

Spectroscopic analysis establishes the authenticity of an object with absolute certainty (see www.spectroscopyforart.com). Once its authenticity has been determined scientifically, its age will be revealed by a stylistic examination.



Spectrographic tests on encrustations of excavated pottery and bronze



- Spectroscopic analysis of encrustations on excavated pottery


(a)- Authentic  silicic encrustations


(b)- Fake encrustations made from synthetic glue and earth



- Spectroscopic analysis of encrustations on excavated bronze objects


(c)- Authentic encrustations made of cuprite and malachite


(d)- Fake encrustations made of glue and paint





The value of art expertise in the scientific age

The judgement of a renowned expert or a famous auction house has, at times, the magic power to push an article�s market value up by as much as a thousandfold. Thus a fine piece of furniture, a painting or an African mask may just as easily cost �1,000 or �1,000,000. This disconcerting difference in value estimates is becoming increasingly common in the international market. This would be conceivable if the appraisal were based on meaningful and verifiable data. Unfortunately this is not always the case.

� 4,500  


� 5,000,000
Auction of June 18, 2006

Over the centuries, well-to-do families and museums the world over have accumulated an unimaginable quantity of precious art treasures of incalculable commercial and art historical value. It is widely held, however, that over half of these works are not authentic. In the absence of scientific methods, such conclusions were based mainly on opinions.
A critical application of the new and accurate methods for ascertaining authenticity to this immense cultural heritage without the consent of its curators is neither thinkable nor desirable.

On the other hand, with the Internet and other media invading the homes of collectors and investors worldwide, it is inevitable that false assertions regarding technical methods for determining authenticity are revealed for what they are. By discrediting scientific analysis, the art market certainly also harms itself. As a result, buyers and investors are increasingly inclined to make their purchases from large and relatively reliable auction houses. There is a tendency of this kind in all sectors and small dealers are forced to close down. But it is precisely the art sector which could escape this trend.

Today gallery owners and art dealers are, in fact, in a position to complement their expert opinions with accurate scientific certificates, thus providing a more dependable guarantee of safer and fairer purchases than the large auction houses. Attitudes, as well as guarantees, need to be changed and scientific analysis should be seen as a useful and advantageous instrument and no longer as an obstacle or a threat.

 A valid method - IR Spectroscopy -  the most widely used analytical method in the chemical industry and in scientific research laboratories, has existed for decades


Get further and detailed information from our web site:




Other scientific methods

The thermoluminescence method

for establishing the authenticity of excavated objects


The thermoluminescence method has been used with success all over the world for a number of decades. There is a vast bibliography, both in print and on the Internet, on the advantages and limits of the method.

Thanks to thermoluminescence, it is possible to tell authentic excavated items from recently manufactured fakes with reasonable accuracy. Some doubts have been cast, however, on this very positive feature ever since the discovery of the method, for the following reason: a number of crystals contained in the subsoil are radioactive and the radiation they emit is absorbed by specific crystals, mostly quartz crystals, contained in the terracotta of the buried objects. The amount of radiation absorbed depends mainly on the length of time they lie buried under the earth, and is measurable.


It is possible for fakers to expose newly-made pottery to artificial radiation sources, thus fooling the measurement instruments. But producing fakes with the use of scientific methods calls for expertise on the subject and expensive instruments, and in fact up to now it has been fairly easy to identify this kind of artificial radiation. It is only a question of time, however, until the artificial radiation method is mature for mass production. From that moment onwards, in order to obtain reliable results, it will be necessary to supplement thermoluminescence measurements with further tests.


This certainty is offered by an examination of the encrustations which generally cover the ceramic surface, a method, used at the naked-eye level, as old as archaeology itself. Today it is possible to carry out this test easily using spectrography, which can distinguish with great reliability between artificially produced encrustations using cement, earth and glue from the authentic mineral salts which have formed over centuries underground.







Other requests may be sent, as always, directly to the Milan laboratory at the following address:

Museo d�Arte e Scienza
Via Q. Sella 4 � 20121 Milano
Tel. 0039 02 72022488
Fax 0039 02 72023156
e-mail: info@museoartescienza.com




Further information on how to recognize fake excavated pottery is available in the third volume of the Art Collector�s Illustrated Handbook (35 pages with 112 coloured photos).



Examples of pages taken from volume 3


Total pages: 8  Illustrations: 20
-  Chapter  Authentic encrustrations






Total pages: 4  Illustrations: 9 - Chapter Mediterranean glass



Total pages: 4  Illustrations: 1
- Copies and Fakes



Total pages: 28  Illustrations: 83
 -  Chapter Restoration -






Total pages: 28 -  Chapter Excavated Chinese pottery



 Total pages: 28 - Chapter Khmer Pottery

   The Art Collector's Illustrated Handbook




Ample further descriptions for ascertaining
in art on our website:


for the individual fields of antiques:






panel paintings and canvases. Reproductions of graphic art work.

statues and
other wooden
art objects.

stone and other materials used for European art objects.

and Asian excavated




 scientific  metHodS
antique and
modern glassware.
African masks and art
statues in wood,
bronze and ivory.
Chinese and Buddhist
art in wood, bronze
and pottery.
for ascertaining authenticity. Laboratories        







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For Information: Tel:+390272022488. Fax:+390272023156.  e-mail:  info@museoartescienza.com




www.MuseoArteScienza.com - Sections of the "Museo d'Arte e Scienza": 6 rooms dedicated to the ascertainment of authenticity in art and antiques, 5 rooms on Leonardo da Vinci's "Treatise on Painting" and his activities in Milan, 5 rooms dedicated to African Art and Buddhist Art, 2 Scientific Laboratories.

www.LeonardoDaVinciMilano.com - Two permanent exhibitions: "Leonardo Citizen of Milan" and  "Appreciating Art through the Eyes of Leonardo" from his "Treatise on Painting".  

www.AuthenticAfricanBronzesandCeramics.com -  Dedicated to the authenticity of African artworks in bronze, stone and pottery. The scientific laboratory of the Museo d�Arte e Scienza has developed valid methods for telling authentic African objects from copies and fakes.

www.ArtAndScienceHandbook.com - The most complete and scientifically valid guide to ascertaining the authenticity of European and non-European antiques on an objective basis (540 pages and more than 2,000 colour illustrations in 3 volumes and 3 languages).

www.Paintingsauthenticity.com -
Information on the authenticity of modern paintings and antique paintings.

www.AntiqueFurnitureAuthenticity.com - A list of possible methods for determining the authenticity of furniture based on objective factors.

www.AfricanArtAuthenticity.com - "Art and Life in Black Africa", The African Art didactic section of the Museum (5 rooms and over 350 objects).

www.SpectroscopyforArt.com - A scientific method for the dating of wood and identification of the wood type used for art objects. Determination of their authenticity through analysis of colours, binders, pigments and other organic substances.

www.Matthaes.org  - The history of the G. Matthaes Foundation from the opening of the painting school in Dresden in 1906 up to the "Museo d'Arte e Scienza" in Milan.

www.CopiesAndFakesInArt.com - Ample further descriptions for ascertaining authenticity in art in the individual fields of antiques.

www.IvoryAuthenticityAndAge.com - Ivory, bone and horn can now be spectroscopically dated and accurately identified.

www.arteautentica.it - The Museum's scientific laboratory is in charge of the investigation of the authenticity in art and antiques and is available to individuals, collectors, art experts, restorers and museums.




Museo d�Arte e Scienza di Gottfried Matthaes S.R.L.
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