Gemmology
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Monday, 26 September 2022


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
Amethyst — specimen 0091

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Moonstone — specimen 0096
Spessartine — specimen 0098
Moonstone — specimen 0099
Amazonite — specimen 0101

— 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

pleonaste — variety of spinel; see pleonaste in ‘Classification’
pneumatolysis — the alteration of rock or mineral crystallisation effected by gaseous emanations from solidifying magma
pollucite — species of mineral; see pollucite in ‘Classification’
poudretteite — species of mineral; faceted specimens exist
Publications

Hainschwang, T., Notari, F., Massi, L., Armbruster, T., Rondeau, B., Fritsch, E., Nagashima, M., 2010 — Hibonite: A New Gem Mineral — Reports a 0.23 g orangy brown crystal, a 0.39 ct step-cut gem later faceted from it, and a 0.71 g crystal of hibonite; all from Myanmar.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Quartz — Features the data of quartz; from ‘Handbook of Mineralogy’.