Gemmology
English | Български
Where am I? > Home > Classification


Quick navigation selector
Classification

Vlasovite
Vlasovite

— A late phase in nepheline syenites, syenitic pegmatites, and along the contact zone of a differentiated alkalic massif (Lovozero Massif, Russia) (Anthony et al., 2001—2005). Faceted specimens are extremely rare.

Specimen figured

Vlasovite — specimen 0006 — weight: 0.22 ct; shape: cushion triangle. Very clean specimen; very good brilliant style cut. The specimen is from the series mentioned by Overlin, 2012. Source: John Bradshaw, Coast to Coast Rare Stones International.

Classification


The section ‘Classification’ presents descriptions of 171 different kinds of natural gemstones (106 mineral species). The Nickel-Strunz systematic order (10th edition) is used. Specimens of the classes shown below are currently available. Since gemmology does not always follow the systematics of minerals in naming, many popular varieties or just ’names’ are also listed.

Classes after Nickel-Strunz

1. Elements
2. Sulphides & sulphosalts
3. Halides
4. Oxides & hydroxides
5. Carbonates (Nitrates)
6. Borates
7. Sulphates
8. Phosphates, arsenates, vanadates
9. Silicates

List of minerals
Alphabetic list of gemstones
Synthetic stones and simulants

Featured
Cordierite

— In thermally metamorphosed argillaceous sediments and regionally metamorphosed schists, gneisses; in mafic igneous rocks and granites (Anthony et al., 2001—2005). The gemstone bears the name iolite.

Specimen figured

Cordierite — specimen 0214 — weight: 0.18 ct; shape: oval. Very clean specimen; good mixed style cut. Source: Gary Eisenberg, Knoxville, Tennessee.
Cordierite — specimen 0214


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

© 2025 National Museum of Natural History, Sofia (NMNHS)
Use of this website assumes acceptance of our terms of use.

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