Am. Shedrinsky et al., APPLICATION OF PYROLYSIS-GAS CHROMATOGRAPHY AND PYROLYSIS-GAS CHROMATOGRAPHY MASS-SPECTROMETRY TO THE UNMASKING OF AMBER FORGERIES, Journal of analytical and applied pyrolysis, 25, 1993, pp. 77-95
Attempts to forge amber inclusions have been known from ancient times,
when natural materials such as melted amber or copal were used. At th
e very beginning of the Twentieth Century these natural materials were
mostly replaced by Bakelite and similar synthetic polymers. These mat
erials are not transparent and so can readily imitate certain kinds of
milky amber but are useless in terms of transparent ambers with inclu
sions. In the 1940s two new classes of organic materials became availa
ble for amber imitation, i.e. polyester resins and epoxy resins. Both
are transparent, able to dissolve organic dyes and can achieve an appr
opriate degree of hardness, depending on the addition of fillers (e.g.
fiberglass), the structure of the original monomers, and the degree o
f crosslinking. With easy commercial availability and sophisticated ''
artwork'' one can prepare convincing imitations of large transparent a
mber pieces with a wide variety of ''inclusions'' (ants, bees, lizards
, mosquitos, etc.). Py-GC provides a simple test for the unmasking of
such fakes, and Py-GC/MS can identify quite precisely the structures o
f the materials used for these purposes. A growing number of fossil fo
rgeries produced in the Dominican Republic, and sold there and in New
York, have been documented. The results reported are based largely on
forgeries acquired by D. Grimaldi specifically for this study and kept
at the American Museum of Natural History in New York; and from the C
onservation Center's collection of forged artifacts and jewelry made a
vailable by New York galleries and private collectors.