The overall format of previous editions has been maintained and new information has been incorporated in a similar style. This edition has two new chapters, on the manufacture and enhancement of gemstones and the old chapter on the detection of synthetic, imitation and composite stones has been rearranged. In the past decade the development of new synthetics has proceeded apace. Nowadays clean rubies and emeralds need very careful investigation since they could be natural or synthetic. However careful use of the microscope can still elucidate many problems and new instruments are shown in the text.
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Double refraction and dispersion
The specific gravity of gemstones and how to measure it
17 other sections not shown
absorption bands absorption spectrum alexandrite almandine amber angle appearance aquamarine axis bead beryl birefringence brown bubbles Burma carat cat's-eyes centre chalcedony Chapter chromium chrysoberyl cobalt colour colourless containing corundum crystal cubic cultured pearls demantoid di-iodomethane diamond dichroism dispersion distinctive distinguish double refraction doublet effect eyepiece Figure filter fluorescence garnet Gemmological gemmologist gemstones glass green imitations immersed inclusions instrument iron jade jadeite jewellery lapis layer lens lines liquid lustre material method microscope mineral natural stones opal optic orange pale peridot pink Plate polished prism produced properties pyrope quartz rays refractive index refractometer rutile seen shadow edge similar single refraction sinhalite specimen spectra spectroscope spessartine spinel Sri Lanka strong strontium titanate structure surface synthetic corundum synthetic emerald synthetic ruby synthetic spinel synthetic stones table facet topaz tourmaline translucent transparent turquoise ultra-violet light usually Verneuil violet wavelength X-rays yellow zircon