Piypite
Piypite | |
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![]() Green acicular crystals of piypite | |
General | |
Category | Sulfate mineral |
Formula (repeating unit) | K2Cu2O(SO4)2 |
IMA symbol | Piy[1] |
Strunz classification | 7.BC.40 |
Crystal system | Tetragonal |
Crystal class | Pyramidal (4) H-M symbol: (4) |
Space group | I4 |
Unit cell | a = 13.6 Å, c = 4.95 Å; Z = 2 |
Identification | |
Color | Emerald-green, dark green, black |
Crystal habit | Acicular crystals elongated along [001], square cross section, commonly hollow; also as mosslike aggregates |
Cleavage | Perfect, parallel to elongation |
Tenacity | Brittle |
Mohs scale hardness | 2.5 |
Luster | Vitreous to greasy |
Streak | Yellowish green |
Diaphaneity | Transparent to translucent |
Specific gravity | 3.0 - 3.1 |
Optical properties | Uniaxial (+) |
Refractive index | nω = 1.583 nε = 1.695 |
Birefringence | δ = 0.112 |
Pleochroism | Distinct; O = pale green, yellowish green; E = deep green, pale yellowish green |
Solubility | Soluble in water, leaves residue |
References | [2][3][4][5] |
Piypite is a rare potassium, copper sulfate mineral with formula: K2Cu2O(SO4)2. It crystallizes in the tetragonal system and occurs as needlelike crystals and masses. Individual crystals are square in cross-section and often hollow. It is emerald green to black in color with a vitreous to greasy luster.[3][4]
It was first described in 1982 for an occurrence in the Main Fracture of the Tolbachik volcano, Kamchatka Oblast, Russia. It has also been reported from Mount Vesuvius, Italy, and in a slag deposit in the Bad Ems District in the Rhineland-Palatinate, Germany.[3][2] Piypite occurs as a sublimate phase in a fumarole environment. Associated minerals include halite, sylvite, langbeinite, tenorite, hematite, , , urusovite, aphthitalite, , cotunnite, , , euchlorine, , , alarsite, , and lammerite at the type locality in Kamchatka. On Vesuvius, it occurs with paratacamite.[3]
References[]
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85: 291–320.
- ^ a b Piypite on Mindat.org
- ^ a b c d Piypite in the Handbook ov Mineralogy
- ^ a b Piypite data on Webmineral
- ^ Mineralienatlas
- Sulfate minerals
- Tetragonal minerals
- Minerals in space group 79
- Sulfate mineral stubs