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Formula: Mn(PO4).H2O
Hydrated phosphate of manganese,
kieserite group
Crystal system: Monoclinic
Specific gravity: 3.17 meaasured, 3.16 calculated
Hardness: 3½
Streak: Olive-green
Colour: Dark brown to dark greenish black
Environments
Localities
At the type locality, the Serra Branca pegmatite, Pedra Lavrada, Paraíba, Brazil, the
pegmatite consists mainly of
quartz (sometimes of bluish colour),
microcline and muscovite, with
minor amounts of albite and
amblygonite. Additional minerals are
apatite, beryl,
uraninite, elbaite,
tantalite and
secondary uranium
minerals. Also, in the central part of the body isolated pods and masses occur of either
primary
manganese-poor triphylite or
iron-poor triplite, each of them up
to several tons in weight. Purpurite,
rockbridgeite, tavorite,
barbosalite, hureaulite,
eosphorite,
phosphosiderite and several others were observed as alteration
products of these phosphates. An unusual association of carlhintzeite,
colquiriite, pachnolite,
hydrokenoralstonite and
fluellite is
also observed.
Serrabrancaite is an alteration product of triplite and was found
as equant or short-prismatic crystals up to 0.3 mm in size in close association with
vernadite
(AM 85.5.847-849).
Serrabrancaite from the Serra Branca Pegmatite -
Image
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