Tangeite
(repeating unit)CaCu(VO4)(OH) IMA symbol Tg[1] Strunz classification 8.BH.35 Dana classification 41.05.01.06 Crystal system Orthorhombic Crystal class Disphenoidal (222)
H-M symbol: (2 2 2) Space group P212121 Unit cell a = 7.45 Å, b = 9.26 Å
c = 5.91 Å; Z = 4 Identification Color Yellow, yellow-green, olive green, green to dark green Crystal habit Rarely as short prismatic crystals, commonly as fibrous to botryoidal encrustations Cleavage Perfect on {010}, good on {001} Tenacity Brittle Mohs scale hardness 3.5 Luster Vitreous, pearly on cleavage faces Streak Light yellow green Diaphaneity Transparent, Translucent Specific gravity 3.75 - 3.84 Optical properties Biaxial (-) Refractive index nα = 2.010 nβ = 2.050 nγ = 2.090 Birefringence 0.08 2V angle 83° (measured) References [2][3][4]
H-M symbol: (2 2 2)
c = 5.91 Å; Z = 4
Tangeite, also known as calciovolborthite, is a calcium, copper vanadate mineral with formula: CaCu(VO4)(OH). It occurs as a secondary mineral that can be found in sandstone and also in the oxidized zones of vanadium bearing deposits.
It was named in 1925 by Aleksandr Evgenievich Fersman for its discovery locality in the Tange Gorge, Ferghana Valley, Alai Mountains, Kyrgyzstan.[2]
References
- v
- t
- e