Gemmology
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Saturday, 25 July 2026


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

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.
Characteristics

Colour in gemstones
Clarity in gemstones
Cut in gemstones

Treatment in gemstones

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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List of minerals
Alphabetic list of gemstones
Synthetic stones and simulants
Classification
Featured

Danburite

— In granite and metamorphosed carbonate rocks associated with hydrothermal activity (Anthony et al., 2001—2005).
Danburite
Euclase
Euclase
Andalusite
Andalusite
Clinozoisite
Clinozoisite
Kornerupine
Kornerupine

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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Simple colour schemeredorangey redreddish orangeorangeorangey yellowyellowgreenish yellowyellowish greenslightly yellowish greengreenvery slightly bluish greenbluish greenvery strongly bluish greengreen-blue or blue-greenvery strongly greenish bluevery slightly greenish bluebluevioletish bluebluish violetvioletbluish purplepurplereddish purplestrongly purplish redslightly purplish redcolourlessgreyblack
Repository
Heliodor — specimen 0426

Some exceptional specimens of gemstones from our ‘Repository’

More specimens of gemstones
Cordierite — specimen 0389
Cordierite — specimen 0390
Agate — specimen 0392
Agate — specimen 0393

— 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

peridot — variety of forsterite; see peridot in ‘Classification’
peridotite — a dense, coarse-grained igneous rock, consisting mostly of olivine and pyroxene
petalite — species of mineral; see petalite in ‘Classification’
petschite — variety from marialite-meionite series; see petschite in ‘Classification’
Publications

Nöggerath, J. J., 1808 — Sanidin — Published in 1808 in ‘Mineralogische Studien über die Gebirge am Niederrhein’; contains the original description of the mineral sanidine.
Gahn, J. G., Berzelius, J., 1815 — Underfökning af nagra i grannskapet af Fahlun funna Fossilier — Published in 1815 in ‘Afhandlingar i Fysik, Kemi och Mineralogi’; contains the original description of the mineral albite.


Gemmology — gemstones
Front page | Introduction | Classification | Repository | Library

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The specimens illustrated in this site do not exist in the collections of the National Museum of Natural History, Sofia.