Gemmology
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Saturday, 23 February 2019


Gemmology — gemstones — characteristics, classification, specimens, library
Chromian diopside

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

Actinolite

— Produced by regional or contact metamorphism of magnesium carbonate, mafic, or ultramafic rocks (Anthony et al., 2001—2005). Faceted specimens are extremely rare.
Actinolite

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
Topaz — specimen 0574

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Carnelian — specimen 0020
Carnelian — specimen 0021
Cordierite — specimen 0025
Grossular-andradite series — specimen 0026

— 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

malaia garnet — variety of pyrope-spessartine series; see malaia garnet in ‘Classification’
Mali garnet — synonym of grandite; grossular-andradite series
marble — a rock; see marble in ‘Classification’
marialite — species of mineral; see marialite in ‘Classification’
Publications

Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Magnetite — Features the data of magnetite; from ‘Handbook of Mineralogy’.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Bromellite — Features the data of bromellite; from ‘Handbook of Mineralogy’.