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Formula: Cu9Fe9S16
Sulphide, talnakhite group
Crystal System: Tetragonal
Specific gravity: 4.36 measured, 4.37 calculated
Hardness: 4
Streak: Black
Colour: Yellow, tarnishes to pinkish brown to a heavy purplish
Common impurities: Ni
Environments
Plutonic igneous environments
Pegmatites
Mooihoekite is commonly associated with copper,
cubanite, haycockite,
mackinawite, magnetite,
moncheite, pentlandite,
sphalerite and troilite
(Mindat).
Localities
The type locality is the Mooihoek Farm 255 KT, Burgersfort, Sekhukhune District, Limpopo, South Africa. The deposit, which
was once mined for platinum, is a pipe-shaped
hortonolite-dunite
pegmatite in the
norite zone of the complex. Mooihoekite and
haycockite were found in small massive sulphide samples from the sulphide-poor
hortonolite-dunite. In polished
sections, mooihoekite occurs in areas up to 1 mm2 and as an intergrowth with
haycockite. The larger areas of mooihoekite commonly show
fractures filled with veinlets of magnetite. Other irregular fractures are filled
with gangue or with a valleriite-type
mineral. Troilite always occurs with a
copper-rich rim; other minerals are a
copper-bearing pentlandite,
mackinawite, sphalerite and
moncheite
(AM 57.689-708).
In the Duluth Gabbro, Minnesota, USA, mooihoekite occurs in
troctolite, associated with
haycockite, copper,
troilite, pentlandite,
cubanite and magnetite
(AM 57.689-708, HOM).
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