Satin spar (German: atlasspat, atlasspath, atlasstein), less commonly atlas spar — is a trivial, partly obsolete name for fibrous varieties of two minerals, gypsum and calcite,[1]: 40 possessing a characteristic silky (satin) luster. Despite their very low hardness (2 or 3 on the Mohs scale), both atlas (satin) spars (especially selenite) are widely used as ornamental stones.
| Satin spar | |
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It should be understood that both of the listed minerals, despite their name of “spars”, do not strictly belong to the number of the most well-known under this name feldspars — both from the point of view of chemical composition and from the standpoint of classical mineralogy.
Main minerals and varieties
edit- Selenite is a fibrous variety of gypsum,[1]: 527 the most common form of satin spars;
- Gypsum, satin spar[2]: 429 in the form of a lustrous fibrous variety, not, however, defined as selenite;[3]: 217
- Calcite or calcite spar is a fibrous variety[2]: 429 superficially resembling selenite,[4]: 169 but much less common in nature;
- Aragonite is one of the polymorphic natural varieties of calcite,[2]: 429 sometimes having the same satin effect.
Satin Spars Gallery
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See also
editReferences
edit- ^ a b Krivovichev V. G. Mineralogical glossary. Scientific editor A. G. Bulakh. — St.Petersburg: St.Petersburg Univ. Publ. House. 2009. — 556 p. — ISBN 978-5-288-04863-0. (in Russian)
- ^ a b c G. F. Herbert Smith. Gemstones. 14th ed., reviewed by F. C. Phillips. — London, Chapman & Hall, 1972. — 580 p. ISBN 0412108909
- ^ R. A. Lidin, L. L. Andreeva, V. A. Molochko. Constants of inorganic substances: handbook. 3rd ed., reprinted, edited by R. A. Lidin. — Москва: Дрофа, 2008 г. — 685 с. (in Russian)
- ^ Boris Cantor. Collecting Minerals. 2nd edition, revised and enlarged. — Moscow: Nedra, 1991. — 173 p. (in Russian)
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