Gemmology
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Thursday, 17 September 2026


Gemmology — gemstones — characteristics, classification, specimens, library
Hackmanite

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
Rose quartz — specimen 0188

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Opal — specimen 0227
Malaia garnet — specimen 0230
Danburite — specimen 0234
Malaia garnet — specimen 0238

— 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

binghamite — a rock; see binghamite in ‘Classification’
biotite — a series or subgroup of the mica group
black spinel — synonym of pleonaste
bloodstone — variety of chalcedony; see bloodstone in ‘Classification’
Publications

Johnson, M. L., McClure, S. F., DeGhionno, D. G., 1996 — Some Gemological Challenges in Identifying Black Opaque Gem Materials — Among the most difficult gems to identify are those that are black and opaque. To identify a black opaque material, every possible mineral, and many rocks and manufactured substances, must be considered.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Hibonite — Features the data of hibonite; from ‘Handbook of Mineralogy’.