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Formula: [Pb32(O,◻)21](AsO4)2[(Si,As,V,Mo)O4]2Cl10
Lead oxychloride ( oxychorides have both oxygen and chlorine atoms attached to lead atoms
in a single molecule; other components may also be present), arsenic-,
vanadium- and molybdenum-
bearing mineral
Crystal System: Monoclinic
Specific gravity: 8.15 calculated for the empirical formula
Streak: White
Colour: Bright orange
Environments
Metamorphic environments
Hydrothermal environments
Hereroite is a relatively new mineral, approved in 2011 and to date (March 2025) reported only from
the type locality.
Localities
At the type locality, the Kombat Mine, Kombat, Otavi Constituency, Otjozondjupa Region, Namibia, the orebodies contain
primary lead -
copper - zinc -
silver sulphides that were originally emplaced hydrothermally as fracture
fillings; they were subsequently modified by hydrothermal and metasomatic replacement events, including a phase of
iron - manganese silicification. These
events created a range of lead -
manganese - iron silicate minerals in
the deposit, and a variety of late-stage lead-oxyhalide minerals including
hereroite and vladkrivovichevite.
Work in the Mendip Hills, where similar minerals are found, indicates that the oxychlorides are formed at the end of
the paragenetic process, at low temperatures and over a wide range of pH (acidity) conditions. Similar conditions
probably prevailed at the Kombat mine when hereroite and
vladkrivovichevite crystallised.
Hereroite is relatively abundant on the type specimen as transparent to translucent intergrown glassy orange
grains. The individual grains are generally less than 1 mm in size and they form aggregates up to ~3 mm. On one corner
of the specimen hereroite forms relatively well defined crystals to ~0.5 mm. Hereroite and
vladkrivovichevite are associated with other oxyhalide minerals
including asisite, damaraite,
kombatite and sahlinite. On the
type specimen, asisite is most abundant as glassy greenish yellow crystalline
masses up to 3 mm across. Kombatite also occurs as orange-brown aggregates
of grains (<1 mm across) which are visually very similar to hereroite. The matrix of the specimen is made up of
clear to white granular vein quartz containing irregular grains of oxychloride
minerals, barysilite, abundant
manganese silicates, rare
native copper and minute grains, less than 0.2 mm, of
manganese oxyhydroxide minerals. These have not been identified due to their
small size, but other oxychloride specimens from the Kombat mine typically contain a mixture of
hausmannite, jacobsite and
manganite
(MM 76.4.883-890).
Hereroite from the Kombat Mine - Image
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