Okenite
| Okenite | |
|---|---|
|
Okenite | |
| General | |
| Category | Phyllosilicate |
| Formula (repeating unit) | CaSi2O5·2H2O |
| Strunz classification | 09.EA.40 |
| Crystal symmetry | Triclinic Space group: P1 or P1 |
| Unit cell | a = 9.69 Å, b = 7.28 Å, c = 22.02 Å; α = 92.7°, β = 100.1°, γ = 110.9°; Z=2 |
| Identification | |
| Color | White, may show slightly yellow or blue tint |
| Crystal habit | Bladed crystals, typically fibrous, clusters of curved crystals and radial balls |
| Crystal system | Triclinic |
| Twinning | Lamellar |
| Cleavage | Perfect on {001} |
| Tenacity | Elastic |
| Mohs scale hardness | 4½-5 |
| Luster | Vitreous, pearly |
| Diaphaneity | Transparent, translucent |
| Specific gravity | 2.28 - 2.33 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.512 - 1.532 nβ = 1.514 - 1.535 nγ = 1.515 - 1.542 |
| Birefringence | δ = 0.003 - 0.010 |
| 2V angle | Measured: 60° |
| References | [1][2][3] |
Okenite (CaSi2O5·2H2O)[2] is a silicate mineral that is usually associated with zeolites. It most commonly is found as small white "cotton ball" formations within basalt geodes. These formations are clusters of straight, radiating, fibrous crystals that are both bendable and fragile.[4]
Discovery and occurrence
It was first described in 1828 for an occurrence at Disko Island, Greenland and named for German naturalist Lorenz Oken (1779–1851).[3]
Minerals associated with okenite include apophyllite, gyrolite, prehnite, chalcedony, goosecreekite and many of the other zeolites. Okenite is found in India, mainly within the state of Maharashtra. Other localities include Bulla Island, Azerbaijan; Aranga, New Zealand; Chile; Ireland and Bordo Island in the Faroe Islands.[2]
References
- ↑ Okenite in the Handbook of Mineralogy
- ↑ 2.0 2.1 2.2 Okenite on Mindat.org
- ↑ 3.0 3.1 Okenite data on Webmineral
- ↑ "OKENITE (Hydrated Calcium Silicate Hydroxide)". Galleries.com. Retrieved 2013-07-27.
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