Diaspore
Diaspore | |
---|---|
![]() | |
General | |
Category | Oxide mineral |
Formula (repeating unit) | |
IMA symbol | Dsp[1] |
Strunz classification | 4.FD.10 |
Crystal system | Orthorhombic |
Crystal class | Dipyramidal (mmm) H–M symbol: (2/m 2/m 2/m) |
Space group | Pbnm |
Unit cell | a = 4.4007(6) Å b = 9.4253(13) Å c = 2.8452(3) Å; Z = 4 |
Identification | |
Color | White, pale gray, colorless, greenish gray, brown, pale yellow, pink, purple; may exhibit color change |
Crystal habit | Platy, elongated to acicular crystals; also stalactitic, foliated, scaly, disseminated, and massive |
Twinning | Forms heart shaped twins on {021} or pseudohexagonal aggregates |
Cleavage | {010} perfect, {110} distinct, {100} in traces |
Fracture | Conchoidal |
Tenacity | Very brittle |
Mohs scale hardness | 6.5–7.0 |
Luster | Adamantine, vitreous, pearly on cleavage faces |
Diaphaneity | Transparent to translucent |
Specific gravity | 3.1–3.4 |
Optical properties | Biaxial (+) |
Refractive index | n n n |
Birefringence | |
Pleochroism | Strong |
2V angle | Measured: 84–86° Calculated: 80–84° |
Dispersion | r < v, weak |
Fusibility | Infusible |
Solubility | Insoluble |
Other characteristics | Decrepitates releasing water in closed tube on heating |
References | [2][3] |
Diaspore (/ˈdaɪ.əˌspɔːr/) – also called diasporite, empholite, kayserite, or tanatarite – is an aluminium hydroxide oxide mineral,
The mineral occurs as an alteration product of corundum or emery and is found in granular limestone and other crystalline rocks. Well-developed crystals are found in the emery deposits of the Ural Mountains and at Chester, Massachusetts, and in kaolin at Schemnitz in Hungary. If obtainable in large quantity, it would be of economic importance as a source of aluminium.[5]
Diaspore, along with gibbsite and boehmite, is a major component of the aluminium ore bauxite.[3]
It was first described in 1801 for an occurrence in Mramorsk Zavod, Sverdlovskaya Oblast, Middle Urals, Russia. The name, which was coined by René Just Haüy,[6] is from the Ancient Greek διασπείρω meaning "to scatter", in allusion to its decrepitation on heating.[2]
Csarite, ottomanite, Turkizite and zultanite are trade names for gem-quality diaspore (also known as Turkish diaspore) from the İlbir Mountains of southwest Turkey.[7]
References
[edit]- ^ Warr, L. N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b Handbook of Mineralogy
- ^ a b Klein, Cornelis; Hurlbut, Cornelius S. (1985). Manual of Mineralogy (20th ed.). Wiley. p. 318. ISBN 0-471-80580-7.
- ^ "The mineral diaspore". minerals.net. Retrieved 2014-06-10.
- ^ a b public domain: Spencer, Leonard James (1911). "Diaspore". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 8 (11th ed.). Cambridge University Press. pp. 168–169. One or more of the preceding sentences incorporates text from a publication now in the
- ^ Spencer 1911.
- ^ Hatipoğlu, Murat; Türk, Necdet; Chamberlain, Steven C.; Akgün, A. Murat (2010). "Gem-quality transparent diaspore (zultanite) in bauxite deposits of the İlbir Mountains, Menderes Massif, SW Turkey". Mineralium Deposita. 45 (2): 201–205. doi:10.1007/s00126-009-0262-2.