BlueChart Gemstones Identification
Natural / Treated / Synthetic / Imitation
by Nicolas Lazzarelli. Updated Edition 2019

	The gemstones identification tables present 141 minerals and are organized by refractif index. With indication of groups, species, sub-species and varieties, refractif index, refractif index range, birefringence & doubling, chrystal system, optic character & sign, specific gravity, specific gravity range, and hardness.
	The description of distinctive characteristics, typical inclusions and common treatments, help to eliminate all possibilities but one. They also give you hints which properties to test in order to double check the result.
	A description of pleochroism
	79 linear absorption spectra as seen with a diffraction grating spectroscope.
	Last but not least the specific gravity, combined with the optical properties are very helpful to identify rough stones or sometimes double check cut stones.
	The index contains 270 entries.
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