Gemmology
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Friday, 27 January 2023


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
Chalcedony — specimen 0695

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Malaia garnet — specimen 0247
Benitoite — specimen 0248
Topaz — specimen 0253
Marialite-meionite series — specimen 0255

— 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

phenakite — species of mineral; see phenakite in ‘Classification’
phonolite — a rare extrusive igneous rock, of intermediate chemical composition between felsic and mafic
phosphophyllite — species of mineral; faceted specimens exist
phosphosiderite — species of mineral; see phosphosiderite in ‘Classification’
Publications

Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Serendibite — Features the data of serendibite; from ‘Handbook of Mineralogy’.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Sapphirine — Features the data of sapphirine; from ‘Handbook of Mineralogy’.