Images
Formula: Al2(GeO4)F2
Germanate, krieselite may be considered as a
gallium-bearing mineral because, although the IMA formula does not include Ga,
generally Ga substitutes for some Al.
Crystal System: Orthorhombic
Specific gravity: 4.069 calculated
Hardness: 5½ to 6½
Streak: White
Colour: Beige to white
Luminescence: Not fluorescent under UV
Common impurities: C
Environments
Sedimentary environments
Hydrothermal environments
Krieselite was approved in 2003 but to date (July 2022) it has been reported only from the type locality.
Localities
At the type locality, the Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia, krieselite occurs in
tennantite-chalcocite-galena-germanite
ore. It forms hemispherical aggregates, up to 200 μm, and fibrous crusts, associated with
quartz, wulfenite,
anglesite and graphite. Fibres are
up to 50 × 5 μm and form wedge-shaped aggregates of fine lamellae.
(AM 96.1656).
At the 29th level of the mine krieselite was associated with
schneiderhöhnite and stottite
(HOM).
Back to Minerals