Gemmology
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Wednesday, 20 January 2021


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 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

Sanidine

— Most common in felsic volcanic rocks; in volcanic glass; also from mafic, high-temperature contact metamorphic, and hydrothermally altered rocks; from eclogite nodules in kimberlite (Anthony et al., 2001—2005).
Sanidine

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
Achroite — specimen 0370

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Malaia garnet — specimen 0048
Hyacinth — specimen 0051
Green beryl — specimen 0059
Topaz — specimen 0070

— 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

sellaite — species of mineral; faceted specimens exist
seminavette — rare shape in faceting a gemstone
seraphinite — variety of clinochlore
serendibite — species of mineral; see serendibite in ‘Classification’
Publications

Hoffmann, C. A. S., 1811 — Grossular — Published in 1811 in ‘Handbuch der Mineralogie’; contains the original description of the mineral grossular.
Ludwig, C. F., 1803 — Sippschaft des granats. Pyrop — Published in 1803 in ‘Handbuch der Mineralogie nach A. G. Werner’; contains the original description of the mineral pyrope.