Kobokoboite

kobokoboite

frondelite

keckite

planerite

Images

Formula: Al6(PO4)4(OH)6.11H2O
Hydrated phosphate
Crystal system: Triclinic
Specific gravity: 2.21 measured, 2.287 calculated
Hardness: 2
Streak: White
Colour: Pearly white
Luminescence: Not fluorescent
Environments

Pegmatites

Localities

At the type locality, the Kobokobo pegmatite, Mwenga Territory, South Kivu, DR Congo, kobokoboite forms 0.1 to 0.15 mm thick crusts and coatings of pearly white, glistening, platy crystals, usually on a matrix of frondelite and keckite. Other associated minerals reported include a fine-grained mixture of planerite, variscite and wavellite, as well as muscovite-2M2, evansite and hydroxylapatite. Individual crystals of kobokoboite are rectangular plates or flattened blades. The crystals have a pearly lustre, are translucent but transparent on edge and have a white streak. The fracture is irregular and the tenacity is brittle (EJM 22.2.305-308).
Kobokoboite is a secondary mineral formed by weathering of the upper branch of a zoned albite - beryl - microcline pegmatite of the LCT (lithium - cesium - tantalum) family (HOM).
Kobokoboite from the Kobokobo pegmatite - Image

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