Gemmology
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Tuesday, 20 November 2018


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

Bastnäsite-(Ce)

— The most abundant rare earth elements-bearing mineral, typically hydrothermal, although primary igneous occurrences are known; in granite and alkali syenites and pegmatites; in carbonatites (Anthony et al., 2001—2005). Faceted specimens are very rare.
Bastnäsite-(Ce)

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
Rock crystal — specimen 0197

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Agate — specimen 0321
Agate — specimen 0322
Agate — specimen 0325
Indicolite — specimen 0329

— 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

lazulite — species of mineral; see lazulite in ‘Classification’
lazurite — variety of haüyne; constituent of lapis lazuli; see lazurite in ‘Classification’
leucite — species of mineral; see leucite in ‘Classification’
limestone — a sedimentary rock composed largely of the minerals calcite and aragonite
Publications

Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Magnetite — Features the data of magnetite; from ‘Handbook of Mineralogy’.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Bromellite — Features the data of bromellite; from ‘Handbook of Mineralogy’.