| Saponite | |
|---|---|
| General | |
| Category | montmorillonite, smectite, phyllosilicate |
| Chemical formula | (½Ca,Na)0.33(Mg,Fe+2)3(Si,Al)4O10(OH)2·4H2O |
| Identification | |
| Color | white, yellow, red, green, blue |
| Crystal habit | Granular - Massive |
| Crystal system | monoclinic - Prismatic C 2/m |
| Cleavage | {001} perfect |
| Mohs scale hardness | 1.5 |
| Luster | Greasy, dull |
| Streak | white |
| Diaphaneity | partially transparent to opaque |
| Specific gravity | 2.3 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.479 - 1.490 nβ = 1.510 - 1.525 nγ = 1.511 - 1.527 |
| Birefringence | δ = 0.032 - 0.037 |
| Other characteristics | not radioactive |
| References | [1][2] |
Saponite is a monoclinic mineral of the montmorillonite group. Its chemical formula is (½Ca,Na)0.33(Mg,Fe+2)3(Si,Al)4O10(OH)2·4H2O. It is soluble in H2SO4. It was first described in 1840 by von Svanberg. Varieties of saponite are griffithite, bowlingite and sobotkite.
It is soft, massive, and plastic, and exists in veins and cavities in serpentinite and basalt. The name is derived from the Greek sapo, soap. Other names include bowlingite; mountain soap; piotine; soapstone.
Localities
Saponite is found in Ząbkowice Śląskie in Silesia, Svärdsjö in Dalarna, Sweden and in Cornwall, UK. The soap stone of Cornwall is used in the porcelain factory. Saponite is also found in the "dark rims" of chondrules in carbonaceous chondrites and seen as a sign of aqueous alteration.[3]
Other
The Strunz classification is VIII/H.20-20, the cell parameters are a = 5.3, b = 9.16, c = 12.4, and the space group is C 2/m.
References
- ^ http://webmineral.com/data/Saponite.shtml Webmineral
- ^ http://www.mindat.org/min-3528.html Mindat
- ^ Zolensky, Michael; Barrett, Ruth; Browning, Lauren (July 1993). "Mineralogy and composition of matrix and chondrule rims in carbonaceous chondrites". Geochimica et Cosmochimica Acta 57 (13): 3123–3148. doi:.
This article contains material from the U.S. Bureau of Mines Dictionary of Mining, Mineral, and Related Terms.
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