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Friday, 21 July 2017

Gemmology — gemstones — characteristics, classification, specimens, library
Smoky quartz


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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— In granite and metamorphosed carbonate rocks associated with hydrothermal activity (Anthony et al., 2001—2005).

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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Heliodor — specimen 0529

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Malaia garnet — specimen 0243
Malaia garnet — specimen 0247
Benitoite — specimen 0248
Topaz — specimen 0253

— 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.

girdle — a small belt separating the two parts of faceted stone — crown and pavilion
glass — natural glass; see also tektite
gneiss — a common and widely distributed type of rock formed by regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks
goethite — species of mineral; constituent of binghamite

Sundius, N., 1946 — The classification of the hornblendes and the solid solution relations in the amphibole group — Published in 1946 in ‘Sveriges Geologiska Undersökning’; contains the original description of the mineral ferro-actinolite.
Bruun-Neergard, T. C., 1807 — De la haüyne, nouvelle substance minérale — Published in 1807 in ‘Journal des Mines’; contains the original description of the mineral haüyne.