Gemmology
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Thursday, 24 September 2020


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

Kyanite

— In gneisses, schists, included pegmatites, and quartz veins, from regional metamorphism of sedimentary rocks (Anthony et al., 2001—2005).
Kyanite

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
Sapphire — specimen 0326

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Milky quartz — specimen 0042
Indicolite — specimen 0043
Milky quartz — specimen 0044
Malaia garnet — specimen 0048

— 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

sedimentary rock — one of the three main rock types; formed by the deposition of material at the Earth’s surface and within bodies of water
sellaite — species of mineral; faceted specimens exist
seminavette — rare shape in faceting a gemstone
seraphinite — variety of clinochlore
Publications

Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Orthoclase — Features the data of orthoclase; from ‘Handbook of Mineralogy’.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Sanidine — Features the data of sanidine; from ‘Handbook of Mineralogy’.