Gemmology
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Tuesday, 20 August 2019


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

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

Gadolinite-(Y)

— In granite and alkalic granite pegmatites (Anthony et al., 2001—2005). Faceted specimens are extremely rare.
Gadolinite-(Y)

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
Verdelite — specimen 0494

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Oregon sunstone — specimen 0447
Vesuvianite — specimen 0486
Hambergite — specimen 0487
Hyacinth — specimen 0488

— 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

hessonite — variety of grossular; see hessonite in ‘Classification’
hexagon — a shape in faceting a gemstone
hibonite — species of mineral; faceted specimens exist (Hainschwang, Notari, Massi, Armbruster, Rondeau, Fritsch, Nagashima, 2010)
hibschite — variety of grossular
Publications

Ludwig, C. F., 1804 — A. G. Werners Mineral — System vom Jahre 1803. Erste Klasse Erdige Fossilien. VI. Kalk — Geschlecht — Published in 1804 in ‘Handbuch der Mineralogie nach A. G. Werner’; contains the original description of the mineral anhydrite.
Jasche, C. F., 1817 — Das Rothmanganerz in der Gegend von Elbingerode am Harz — Published in 1817 in ‘Kleine Mineralogische Schriften’; contains the original description of the mineral rhodonite.