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Formula: CaMn3+2(AsO4)2(OH)2
Valence: CaMn3+2(As5+O4)2(OH)2
Arsenate,
tsumcorite group,
manganese-bearing mineral
Crystal system: Monoclinic
Specific gravity: 3.77 measured, 3.75 calculated
Hardness: 3
Streak: Light brown
Colour: Brown-red to dark reddish orange
Common impurities: V,Fe,Ni,Co,Zn,Al
Environments
Localities
At the Jote Mine, Pampa Larga mining district, Tierra Amarilla, Copiapó Province, Atacama, Chile,
manganlotharmeyerite has been found on a limonite matrix
(Mindat photo).
Manganlotharmeyerite from the Jote
Mine - Image
The type locality, the Starlera Mine, Starlera Valley, Ferrera, Viamala Region, Grisons, Switzerland,
breccias with a matrix rich in asbestiform (fibrous)
magnesioriebeckite are abundant and characteristic of the deposit.
Braunite is the main ore-mineral, whereas the
manganese-silicates rhodonite and
spessartine are absent. Numerous discordant veins of
roméite, tilasite,
calcite ± aegirine,
phlogopite, fluorite and
tripuhyite up to 30 cm in thickness cut the ore. Aligned in the main S1
schistosity are strontium-bearing
baryte, As-poor fluorapatite,
Sb-free rutile, and possibly Ce-rich
roméite and Sb-bearing pyrophanite.
A later paragenesis, overgrowing S1, contains As-rich fluorapatite,
REE-rich roméite,
bergslagite, Sb-rich rutile,
Sb-bearing pyrophanite and Sb–As-bearing
titanite, as well as aegirine
porphyroblasts. Arsenic-rich
fluorapatite, bergslagite,
antimony-bearing rutile and
antimony-bearing pyrophanite
occur in fractures within titanite crystals.
Manganlotharmeyerite has been discovered in small (cm to dm), open fissures inside massive
braunite ore. The manganlotharmeyerite forms elongate platy crystals
and aggregates up to 1 mm in length that are mostly translucent. Manganlotharmeyerite is associated with
calcite, tilasite and
sailaufite, a new (in 2002) species discovered in the Sailauf rhyolite
quarry, Spessart, Germany. The sailaufite from Starlera forms thin platy
brown crystals grouped in rosettes up to 1 mm across. Manganlotharmeyerite and
sailaufite represent the latest stage of the retrograde remobilisation of
arsenic in the Starlera ores
(CM 40.6.1597-1608).
Manganlotharmeyerite from the Starlera Mine -
Image
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