Ammineite is the first recognized mineral containing ammine groups. Its formula is [CuCl2(NH3)2]. The mineral is chemically pure. It was found in a guano deposit in Chile.[2][3] At the same site other ammine-containing minerals were later found:[4][5][6][7]
Ammineite | |
---|---|
General | |
Category | Chloride mineral |
Formula (repeating unit) | CuCl2(NH3)2 |
IMA symbol | Amm[1] |
Crystal system | Orthorhombic |
Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
Space group | Cmcm |
Unit cell | a = 7.79, b = 10.64 c = 5.84 [Å] (approximated) |
Identification | |
Color | Blue |
Crystal habit | Hypidiomorphic crystals; powdery masses |
Mohs scale hardness | 1 |
Luster | Vitreous |
Streak | Light blue |
Specific gravity | 2.38 (calculated) |
Pleochroism | Dark blue to light blue |
References | [2][3] |
The characteristic features of the structure of ammineite are:[2]
Ammineite coexists with atacamite, darapskite, halite and salammoniac.[2]
Ammineite is supposed to be a result of an interaction of an earlier copper mineral, likely from a plutonic rock, with ammonia in guano. Ammonia may be produced in decomposition of compounds like urea or uric acid.[2]