Khinite
| Khinite | |
|---|---|
| General | |
| Category | Category:Tellurate minerals |
| Formula (repeating unit) | PbCu3TeO6(OH)2 |
| 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 |
| Density | 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 | |
Khinite is a rare tellurate mineral with the formula Pb2+Cu2+3TeO6(OH)2[1][2][3] 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.[4] The tetragonal dimorph of khinite is called parakhinite.
Occurrence & name
Both khinite and parakhinite were first identified in 1978 in the Old Guard Mine (Royal Guard Mine), Tombstone District, Cochise County, Arizona, USA. They were named after Ba-Saw Khin, a Burmese-American mineralogist.[1] They are often found together with tenorite, quetzalcoatlite, quartz, gold, dugganite, chrysocolla, chlorargyrite, bromargyrite, xocomecatlite, and tlapallite.[1][4] Khinite and parakhinite are found in multiple mines across Mexico and the USA.
Parakhinite
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.[1][3][5][6]
References
- 1 2 3 4 "Khinite: Khinite mineral information and data.". www.mindat.org. Retrieved 2016-10-28.
- ↑ Barthelmy, Dave. "Khinite Mineral Data". www.webmineral.com. Retrieved 2016-10-28.
- 1 2 Williams, S.A. (1978). "Khinite, parakhinite, and dugganite, three new tellurates from Tombstone. Arizona" (PDF). American Mineralogist. 63: 1016–1019.
- 1 2 "Handbook of mineralogy, Khinite" (PDF).
- ↑ Cooper, M. A.; Hawthorne, F. C.; Back, M. E. "The crystal structure of khinite and polytypism in khinite and parakhinite". Mineralogical Magazine. 72 (3): 763–770. doi:10.1180/minmag.2008.072.3.763.
- ↑ Hawthorne, F. C.; Cooper, M. A.; Back, M. E. "KHINITE-4O [= KHINITE] AND KHINITE-3T [= PARAKHINITE]". The Canadian Mineralogist. 47 (2): 473–476. doi:10.3749/canmin.47.2.473.