Gemmology
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Thursday, 23 March 2017


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 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

Sinhalite

— A rare accessory mineral formed in boron-rich skarns at the contact of limestones with granite or gneiss (Anthony et al., 2001—2005). Faceted specimens are relatively rare. The largest faceted stone is a 158 carat from Sri Lanka (Arem, 1987: 173).
Sinhalite

The section ‘Repository’ contains data and photos of 713 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
Pleonaste — specimen 0670

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Moonstone — specimen 0095
Moonstone — specimen 0096
Spessartine — specimen 0098
Moonstone — specimen 0099

— 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

verdelite — variety of elbaite; see verdelite in ‘Classification’
vesuvianite — species of mineral; see vesuvianite in ‘Classification’
vlasovite — species of mineral; see vlasovite in ‘Classification’
volcanic pipe — usually largely composed of one of two characteristic rock types — kimberlite or lamproite; they are well known as the primary source of diamonds
Publications

Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Scolecite — Features the data of scolecite; from ‘Handbook of Mineralogy’.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Leucite — Features the data of leucite; from ‘Handbook of Mineralogy’.