Gemmology
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Tuesday, 19 March 2024


Gemmology — gemstones — characteristics, classification, specimens, library
Chromian diopside

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

Sinhalite

— A rare accessory mineral formed in boron-rich skarns at the contact of limestones with granite or gneiss (Anthony et al., 2001—2005). Faceted specimens are relatively rare. The largest faceted stone is a 158 carat from Sri Lanka (Arem, 1987: 173).
Sinhalite

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 0733

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Pargasite — specimen 0275
Ruby — specimen 0276
Bytownite — specimen 0284
Chromian pyrope — specimen 0289

— 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

amazonite — variety of microcline; see amazonite in ‘Classification’
amblygonite — species of mineral; see amblygonite in ‘Classification’
amethyst — variety of quartz; see amethyst in ‘Classification’
ametrine — variety of quartz; see ametrine in ‘Classification’
Publications

Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Ferro-actinolite — Features the data of ferro-actinolite; from ‘Handbook of Mineralogy’.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Tremolite — Features the data of tremolite; from ‘Handbook of Mineralogy’.