Images
Formula: KLiAl1.5☐0.5(Si3.5Al0.5)O10F2
Phyllosilicate (sheet silicate), mica group
Crystal System: Monoclinic
Specific gravity: 2.94 measured, 2.898 calculated
Hardness: ~3
Streak: Colourless, white
Colour: Silvery white
Environments
Fluorluanshiweiite is a relatively new mineral, approved in 2019 and to date (June 2025) reported only
from the type locality.
Localities
At the type locality, the Nanyangshan 703 deposit, Nanyangshan pegmatite field, Lushi County, Sanmenxia, Henan,
China, the rare metal mineralisation is hosted in an
lithium - cesium -
tantalum (LCT) granitic
pegmatite formed in the late stage of the evolution of the
pegmatite-forming magmatic liquid.
Fluorluanshiweiite is closely associated with luanshiweiite,
polylithionite, cookeite,
albite, quartz and an unknown
cesium-rich mica, and it is commonly
found with spodumene,
montebrasite, elbaite,
fluorapatite, pollucite
and nanpingite.
Tantalite-(Mn),
columbite-(Mn),
bismutotantalite,
stibiotantalite,
oxynatromicrolite and
fluornatromicrolite are some other associated minerals.
Fluorluanshiweiite occurs mostly in cookeite as a flaky residue,
replaced by cesium-rich mica, or
in the form of scale aggregates. Most individual grains are less than 1 mm in size, with the largest being ~1 cm,
and the periphery is replaced by cookeite. Fluorluanshiweiite is
silvery white as a hand specimen and greyish-white to colourless in a thin section, transparent with a white streak;
it has a vitreous lustre and appears pearly on cleavage planes
(Minerals, 10 (2) 93 doi:10.3390/min10020093).
Back to Minerals