BlueChart Gemstone Identification
Natural / Treated / Synthetic / Imitation
by Nicolas Lazzarelli. Updated and Expanded Edition 2025

	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.
	75 collector stones listed separately.
	79 linear absorption spectra as seen with a diffraction grating spectroscope.
	The specific gravity, combined with the optical properties are very helpful to identify rough stones or sometimes double check cut stones.
	A description of pleochroism.
	Reaction with Chelsea filter.
	The index contains 350 entries.
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