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Formula: CuCl2.2NH3
Valence: Cu2+Cl2(N3-H3)2
The first approved mineral with an ammine complex (containing a metal in complex with NH3). As of
September 2023 there were five known ammine complex bearing minerals, ammineite,
chanabayaite, joanneumite,
shilovite and triazolite
(Mindat).
Crystal System: Orthorhombic
Specific gravity: 2.34 calculated
Hardness: 1
Streak: Light blue
Colour: Deep blue to sky blue
Luminescence: Not fluorescent under UV
Solubility: Soluble in hydrochloric acid and in ammonia, in water transforms into an amorphous phase
Environments
Localities
The type locality is Pabellón de Pica, Chanabaya, Iquique, Iquique Province, Tarapacá, Chile. Geotectonically,
Calleta Pabelon de Pica is part of the Coastal Cordillera, in which igneous rocks are predominant. The coarse-grained
host rock of the sample studied consists of amphibole,
plagioclase and minor
clinochlore, and is probably a
hornblende gabbro. A minor
component of the rock sample is intergranular chalcopyrite. The guano
of the Tarapaca region was deposited on these plutonic rocks and was exploited since pre-Inca cultures as fertiliser.
The guano is produced along the coast by guano birds like cormorants, pelicans and boobies. Bird guano is rich in
(NH3), that is a product of the breakdown of urea or uric acid excretions. Ammineite is likely to be the
product of the interaction between NH3 from guano and Cu from the plutonic rocks.
The main component of the mineralisation is halite, that forms coarse-grained
centimetre-thick layers and crack fillings in a hornblende
gabbro. Halite is interspersed
with millimetric to centimetric solution-cavities that are filled with masses of intense blue ammineite and
atacamite. Salammoniac forms
pale blue layers on halite. Narrow voids in
halite are occasionally filled with sulphates and carbonates like
darapskite, glauberite and
thermonatrite.
Ammineite is product of reaction of a copper mineral with guano. It occurs as intense sky-blue hypidiomorphic
(a term used of a rock only some of whose constituents have a distinct crystalline form) grains up to 3 millimeters
across, and also as powdery masses in solution cavities of halite.
Ammineite is deep to sky blue, transparent to translucent, with a vitreous lustre
(CM 48.6.1359-1371).
Ammineite from Pabellón de Pica - Image
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