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Formula: Cu3Zn(OH)6Cl2
Halide, atacamite group, trigonal
paramorph of kapellasite,
which is metastable and also trigonal; herbertsmithite forms a solid solution with
paratacamite (MM 68.527-539)
Crystal System: Trigonal
Specific gravity: 3.85 to 3.95 measured, 3.76 calculated
Hardness: 3 to 3½
Streak: Light green
Colour: Light green, blue-green, emerald green
Environments
Metamorphic environments
Hydrothermal environments
Herbertsmithite is a secondary mineral in the
oxidation zone of polymetallic mineral deposits
(HOM).
Localities
At the type locality, Los Tres Presidentes Mine, Caracoles, Sierra Gorda, Antofagasta Province, Antofagasta, Chile,
herbertsmithite occurs on a white quartzite as scattered to
richly clustered coatings of complex rhombohedra to 1 mm in diameter, or somewhat larger flattened crystals
and aggregates in parallel growth. Associated minerals include flattened
gypsum crystals, radiating needles of opal
pseudomorphs and minor dioptase
(MM 68.527-539).
At the Chah Khouni Mine, Anarak District, Nain County, Isfahan Province, Iran, herbertsmithite occurs
on joint surfaces of metamorphosed dolomitic
limestone coated with limonite
and associated with hemimorphite,
chrysocolla, iranite,
diaboleite and calcite.
Herbertsmithite occurs as crystals with indistinct faces mostly ~0.1 mm across and aggregates of such crystals
(MM 68.527-539).
At the Kali Kafi Mine, Anarak District, Nain County, Isfahan Province, Iran, herbertsmithite occurs
in limonite gossan as grains
mostly <0.1 mm across in confused aggregates. Associated minerals include
wulfenite crystals, hemimorphite,
chrysocolla and rosasite
(MM 68.527-539).
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