Blue Chart Gem Identification
Natural / Treated / Synthetic / Imitation
by Hervé Nicolas Lazzarelli, first edition 2002
 | The gem identification tables present 119 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 distinctif 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 |
 | Last but not least the specific gravity. |
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