Gemmology
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Friday, 23 August 2019


Gemmology — gemstones — characteristics, classification, specimens, library
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GEMMOLOGY — GEMSTONES

characteristics, classification, specimens, library

As gemstones we accept cut specimens of crystals of natural mineral species having a visible transparency and certain durability. From over 4800 known minerals (according to data of the International Mineralogical Association), approximately 150 satisfy the above conditions and form crystals of sufficient size to be cut.

The section ‘Classification’ presents descriptions of 171 different kinds of natural gemstones (106 mineral species). The Nickel-Strunz systematic order (10th edition) is used. Since gemmology does not always follow the systematics of minerals in naming, many popular varieties or just ’names’ are listed.

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Classification
Featured

Gadolinite-(Y)

— In granite and alkalic granite pegmatites (Anthony et al., 2001—2005). Faceted specimens are extremely rare.
Gadolinite-(Y)

The section ‘Repository’ contains data and photos of 760 specimens of gemstones. The smallest is just 1.96 mm (0.02 ct) ruby from Mozambique, and the largest — 70.11 mm (326.60 ct) rock crystal from Africa. Besides there are 8 specimens of synthetic stones.

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Repository
Chrysoberyl — specimen 0667

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Jasper — specimen 0600
Turquoise — specimen 0601
Turquoise — specimen 0602
Malachite — specimen 0603

— More from ‘Repository

Currently there are 283 bibliographical references and abstracts to publications with gemmological or mineralogical thematics in the ‘Library’. The section comprises also a glossary with 391 terms.
Library
Glossary

keystone — rare shape in faceting a gemstone
kimberlite — an igneous rock; best known for sometimes containing diamonds
kite — rare shape in faceting a gemstone
kornerupine — species of mineral; see kornerupine in ‘Classification’
Publications

Arem, J. E., 1987 — Color Encyclopedia of Gemstones. 2nd edition — One of the most popular and complete guide to gemstones. Contains descriptions and 344 figures.
Damour, A. A., 1863 — Notice et analyse sur le jade vert. Réunion de cette matière minérale à la famille des Wernerites — Published in 1863 in ‘Comptes Rendus Hebdomadaires des Séances de l’Académie des Sciences’; contains the original description of the mineral jadeite.