Emerald, imitation

A thin layer of dark green beryl had been grown by a hydrothermal technique over the surface of a pale beryl to imitate emerald. It has been suggested that such stones should be called synthetic emerald-beryl doublets (16). The abiHty to grow thin, but not thick, single-crystal diamond on the surface of natural diamond (17) leads to the possibiHty of growing such a thin film colored blue with boron this has been done experimentally (18). 

Emerald.—The emerald is very easy to imitate. That which succeeds best rosidts from the mixture of the oxide of copper with colorless strass. If oxide of cohalt he added, the green obtained presents blue reflexions. The composition which gives the best imitation of natural emerald is as follows —... 

The allusions to Democritus by Vitruvius, writing a century or more before Pliny, seem to apply to the real Democritus. Vitruvius says he wrote several works on the nature of things. Seneca attributes to him the invention of the reverbatory furnace, and the art of imitating natural gems, particularly the emerald, though it is probable that here also the real Democritus is confused with the pseudo-Democritus. 

For imitating gems and semiprecious stones, Pliny says that glass was extensively used, and that it was with great difficulty that the imitations could be distinguished from the genuine. Obsidian, topaz, beryl, carbuncle, sapphire, jasper, opal, onyx, and emerald were thus imitated. 

Nay more than this, there are books, the authors of which I refrain from mentioning, which give instructions how to stain crystal (quartz) in such a way as to imitate emeralds and other transparent stones. . . and there... 

The use of a name for a reagent which is intended to mislead or to conceal the truth from those not adepts, may be illustrated in the following directions for imitating the emerald. 

The materials most commonly used as gems and ornamental stones are listed in Table 2.9. This is by no means a complete listing of all materials ever used in jewelry or for decorative purposes. There are many worked specimens that are one-of-a-kind, made from unexpected materials that were opportunistically obtained. These often pose problems of identification and consequently of conservation, since once a stone has been worked it loses its natural luster and form. Stones have been altered with dyes and heat for thousands of years, so it does not hold true that just because something is in an old artifact or Grandma s necklace that it cannot be dyed or otherwise not natural. Synthetics are relatively new, but imitations are as old as the stones themselves. If someone wanted a red gem, and there were no rubies available, then a garnet or spinel could be used instead. No emeralds Use an olivine (peridot) or green sapphire. A synthetic must have the same composition and internal structure as the natural material, but an imitation just has to look like the natural stone. 

Deny coloring matter of emerald due to organic matter and heated to prove. Imitate color in glass by a small amount of chromium. 

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