Khinite is a rare tellurate mineral with the formula Pb2+Cu2+3TeO6(OH)2.[2][3][4] It crystallizes in the orthorhombic system and has a bottle-green colour. It is often found as dipyramidal, curved or corroded crystals no more than 0.15 mm in size.[5] The tetragonal dimorph of khinite is called parakhinite.
Khinite | |
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General | |
Category | Tellurate minerals |
Formula (repeating unit) | PbCu3TeO6(OH)2 |
IMA symbol | Khn[1] |
Strunz classification | 4.FD.30 |
Dana classification | 33.1.3.1 |
Crystal system | Orthorhombic |
Unit cell | Khinite-4O: a = 5.740 Å, b = 9.983 Å, c = 23.960 Å, Z = 8 Khinite-3T (parakhinite): a = 5.753 Å, c = 17.958 Å, Z = 3 |
Identification | |
Color | Dark green – Bottle green |
Crystal habit | Dipyramidal or curved crystals |
Cleavage | {001} fair |
Tenacity | Brittle |
Mohs scale hardness | 3.5 |
Luster | Vitreous |
Streak | Green |
Diaphaneity | Semitransparent |
Specific gravity | 6.5–7.0 (measured) 6.69 (calculated) |
Optical properties | Biaxial (+) (khinite) Uniaxial (−) (parakhinite) |
Birefringence | δ = 0.055 |
Pleochroism | Yellow green – emerald green |
2V angle | 20o |
Ultraviolet fluorescence | None |
Fusibility | Fuses readily to a brown slag |
Solubility | Soluble in cold acids |
Common impurities | Ca |
References | [1][2][3][4][5][6] |
Both khinite and parakhinite were first identified in 1978 in the Old Guard Mine (Royal Guard Mine), Tombstone District, Cochise County, Arizona, US They were named after Ba-Saw Khin, a Burmese-American mineralogist.[2] They are often found together with tenorite, quetzalcoatlite, quartz, gold, dugganite, chrysocolla, chlorargyrite, bromargyrite, xocomecatlite, and tlapallite.[2][5] Khinite and parakhinite are found in multiple mines across Mexico and the USA.
Parakhinite crystallizes in the tetragonal system. Khinite and parakhinite are also called khinite-4O and khinite-3T, respectively. Khinite and parakhinite are identical in colour and many other properties, like reactivity. They do differ in optical properties: Khinite is biaxial (+), while parakhinite is uniaxial (−). They also have different unit cells.[2][4][6][7]