Images
Formula: Cu(OH)2
Hydroxide
Crystal System: Orthorhombic
Specific gravity: 3.93 measured, 3.94 calculated
Colour: Light blue, blue-green
Solubility: Synthetic material is soluble in cold water, decomposes in hot water and is soluble in acids
Environments
Localities
The type locality is the Jeffrey mine, Val-des-Sources, Les Sources RCM, Estrie, Quebec, Canada. Spertiniite is
a very rare mineral, found in a rodingite dyke exposed in the open pit
near the contact with the host serpentinised
dunite. This portion of the
rodingite consists primarily of fine grained, dense, white
diopside and grossular, partly
coated with pale green vesuvianite.
Chalcocite commonly constitutes the core of the botryoidal masses of
spertiniite, which also contain atacamite. Minor amounts of
copper are associated with spertiniite in the
rodingite. It appears that the spertiniite is a product of the
supergene alteration of
chalcocite. In the area where the spertiniite was found, percolating
water was found to be oxidising, and also quite alkaline, with pH=9.2. These unusual conditions preclude the formation of
copper sulphates, which are the normal alteration products of chalcocite.
Here the solubility is due almost entirely to the cupric ion, Cu2+, and the stable solid phase is cupric
hydroxide Cu2+(OH)2. Any chloride ions available in the groundwater have been essential to the
formation of atacamite
(CM 19.337-340).
Back to Minerals