Images
Formula: Cu2Cl(OH)3
Hydroxylhalide, atacamite group,
paramorph of
atacamite and clinoatacamite
Crystal System: Monoclinic
Specific gravity: 3.6 measured, 3.6 calculated
Hardness: soft
Streak: Light green
Colour: Bluish green to green, pale bluish green in transmitted light
Environments
Botallackite is a secondary
copper
mineral in copper-bearing deposits, in areas with high chlorine
concentrations, or weathered while
exposed to seawater; it is a reaction product of slag immersed in seawater and a weathering product of sulphides
in subsea black smoker deposits
(Webmin, HOM).
Localities
At the type locality, Wheal Cock, Botallack Mine, Botallack, St Just, Cornwall, England, UK, botallackite
occurs as crusts of minute platy
interlaced crystals in a copper deposit, in areas weathered while exposed
to sea water. Associated minerals
include atacamite and
paratacamite
(Mindat, HOM).
At Dalbeattie, Dumfries and Galloway, Scotland, UK, botallackite is associated with
gypsum,
brochantite and connellite
(HOM).
At the Gallagher Vanadium & Rare Minerals Corporation Mine, Cochise county, Arizona, USA, botallackite
occurs as sparse, pale green
needles to 0.2 mm, associated with anglesite,
brochantite
and bromine-bearing chlorargyrite on the mine dump
(R&M 90.4.342).
From the Ahmeek No. 1 Shaft, Ahmeek Mine, Ahmeek, Keweenaw county, Michigan, USA, a photomicrograph, field of view
1.5 mm, shows crystallised light blue botallackite and atacamite
encrusting an epidote crystal
(R&M 97.4.356).
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