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Formula: Pb3Ge(SO4)2(OH)6.3H2O
Germanium-bearing hydrated sulphate containing hydroxyl
Crystal System: Hexagonal
Specific gravity: 4.59 calculated
Hardness: 2½ to 3
Streak: White
Colour: White to pale rose
Environments
Fleischerite is a very rare mineral. Although it was first published in 1960, to date (October 2022)
it has been reliably reported only from the type locality, although there is one other questionable occurrence.
Localities
At the type locality, the Tsumeb mine, Tsumeb, Oshikoto Region, Namibia, fleischerite occurs in the upper
oxidised portion of a dolostone-hosted hydrothermal
germanium-bearing copper- and
arsenic- rich ore deposit (Webmin).
The fleischerite occurs as very slender white to pale rose, prismatic to fibrous crystals to 15 mm in length but
is usually much shorter. The crystals commonly form mats of subparallel individuals or, less commonly, rounded aggregates
of radiating crystals. It occurs in at least four different parageneses:
1. Fleischerite forms roundish, loosely matted white aggregates in paragenesis with
cerussite, small crystals of mimetite
and sooty looking granules of tennantite on a matrix of weathered
tennantite.
2. Fleischerite occurs as a fine coating on a bed of green
plumbojarosite with numerous crystals of olive-green
mimetite, all on a matrix of
dolostone.
3. tiny pink spherules of fleischerite are a sparse component of a very unusual paragenesis that includes
alamosite, anglesite,
hematite, leadhillite,
melanotekite, mimetite and
kegelite. Larsenite,
plumbojarosite,
plumbotsumite and queitite
also form part of this paragenesis, albeit as rarer constituents.
Silky needles of fleischerite to 15 mm in length were found
grown on and through large yellow crystals of anglesite, which were partly
covered by greenish black nodules of melanotekite and perfect rosettes of
pearly kegelite scales with maximum size of 2 mm.
4. The occurrence of fleischerite with other secondary germanium minerals constitutes a fourth paragenesis. A
specimen of germanite ore exists that presents a tiny cavity lined with a
0.3 mm aggregate of green sawtoothed bartelkeite,
söhngeite and spherules of what appear to be a
germanium-rich plumbogummite.
Bridging the same cavity are minute fibrous crystals of fleischerite
(R&M 97.4.348-353).
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