Satin spar explained
Satin spar (de|atlasspat, atlasspath, atlasstein), less commonly atlas spar — is a trivial, partly obsolete name for fibrous varieties of two minerals, gypsum and calcite,[1] 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.
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
- Selenite is a fibrous variety of gypsum,[1] the most common form of satin spars;
- Gypsum, satin spar in the form of a lustrous fibrous variety, not, however, defined as selenite;[2]
- Calcite or calcite spar is a fibrous variety[3] superficially resembling selenite,[4] but much less common in nature;
- Aragonite is one of the polymorphic natural varieties of calcite,[3] sometimes having the same satin effect.
Satin Spars Gallery
See also
Notes and References
- 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)
- 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)
- G. F. Herbert Smith. Gemstones. 14th ed., reviewed by F. C. Phillips. — London, Chapman & Hall, 1972. — 580 p. ISBN 0412108909
- Boris Cantor. Collecting Minerals. 2nd edition, revised and enlarged. — Moscow: Nedra, 1991. — 173 p. (in Russian)
