Gemmology
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Wednesday, 16 August 2017


Gemmology — gemstones — characteristics, classification, specimens, library
Amethyst

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 163 different kinds of natural gemstones (104 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 728 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 7 specimens of synthetic stones.

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Repository
Rock crystal — specimen 0172

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Grossular-hibschite series — specimen 0089
Moonstone — specimen 0095
Moonstone — specimen 0096
Spessartine — specimen 0098

— More from ‘Repository

Currently there are 279 bibliographical references and abstracts to publications with gemmological or mineralogical thematics in the ‘Library’. The section comprises also a glossary with 381 terms.
Library
Glossary

lazurite — variety of haüyne; constituent of lapis lazuli; see lazurite in ‘Classification’
leucite — species of mineral; see leucite in ‘Classification’
limestone — a sedimentary rock composed largely of the minerals calcite and aragonite
linarite — species of mineral; faceted specimens exist; soft
Publications

Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Bustamite — Features the data of bustamite; from ‘Handbook of Mineralogy’.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Xonotlite — Features the data of xonotlite; from ‘Handbook of Mineralogy’.