Gemmology
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Tuesday, 19 March 2024


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

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
Spinel — specimen 0597

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Grossular-andradite series — specimen 0026
Grossular-andradite series — specimen 0027
Andalusite — specimen 0033
Oregon sunstone — specimen 0038

— 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

culet facet — facet at the bottom end of the pavilion of faceted stone; very rare element in the contemporary design
cuprite — species of mineral; faceted specimens reported
cushion — a commonly used shape in faceting a gemstone
cushion triangle — a commonly used shape in faceting a gemstone
Publications

Breithaupt, J. F. A., 1818 — Gattung B. Amblygonit — Published in 1818 in ‘Handbuch der Mineralogie von C. A. S. Hoffmann’; contains the original description of the mineral amblygonite.
Anthony, J. W., Bideaux, R. A., Bladh, K. W., Nichols, M. C. (Eds), 2001—2005 — Triplite — Features the data of triplite; from ‘Handbook of Mineralogy’.