Images
Formula: Al2(PO4)(OH)3.4H2O
Hydrated phosphate
Crystal System: Amorphous
Specific gravity: 1.97 to 2.05 measured
Hardness: 2½
Colour: Pale greenish yellow
Luminescence: Strongly fluorescent in green under UV, due to the presence of
uranium impurities
Common impurities: U
Environments
Plutonic igneous environments
Pegmatites
Bolivarite is an approved mineral species at present (July 2024), but it may turn out to be a variety of
evansite.
Localities
At the Kobokobo pegmatite, Mwenga Territory, South Kivu, DR Congo, bolivarite has been found. This amorphous
mineral was previously considered to be evansite, but further studies show that
it is in fact bolivarite.
The Congolese bolivarite generally occurs in botryoidal masses as a coating on other minerals and is located
especially in the weathering zone and in the phosphate-rich zone of the
pegmatite. Sometimes it also forms veinlets. Its colour varies
from bright and yellowish green to greenish white, the green material being in general richer in
uranium. Bolivarite has a vitreous lustre and a conchoidal fracture. Its
colour and lustre are characteristic and permit a quick distinction between bolivarite and the other aluminum
phosphates or oxides of the Kobokobo pegmatite, such as gibbsite. The
bolivarite locally contains brown undeterminable
inclusions, unevenly distributed and tentatively considered to be xenotime. A
fairly common inclusion is quartz and, more rarely,
autunite and phosphuranylite
are found in the richest uraniferous specimens
(MM 38.418-23).
Bolivarite from the Kobokobo Pegmatite -
Image
At the type locality, Pontevedra, Galicia, Spain, bolivarite occurs in crevices in
granite
(Mindat).
Back to Minerals