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Formula: CeF3
Fluoride of cerium
Specific gravity: 6.13
Hardness: ½ to 5,
Streak: Yellow-white
Colour: Light yellow, darkening to yellow- and red-brown; colourless to pale pink in transmitted light
Solubility: Soluble in sulphuric acid, insoluble in hydrochloric or nitric acid
Weakly RADIOACTIVE
Environments
Plutonic igneous environments
Pegmatites
Hydrothermal environments
Fluocerite-(Ce) occurs in granitic rocks.
(Webmin, HOM).
Localities
There are two co-type localities for fluocerite-(Ce), Broddbo and Finnbo, both at Falun, Dalarna County, Sweden.
At the Bastnäs Mines, Riddarhyttan, Skinnskatteberg, Västmanland County, Sweden, fluocerite-(Ce) is one of the rarest
cerium minerals. It is found as grains in törnebohmite -
bearing cerite-(CeCa), and is replaced by bastnäsite along
cleavage cracks in the fluocerite
(MinRec 35.3.196).
Near Odegi, Nasarawa, Nigeria, fluocerite-(Ce) occurs in albite
pegmatites
(Dana).
The Wellington Lake pegmatite, Park county, Colorado, USA, is a
niobium-yttrium-fluorine type
pegmatite, known for its unusual rare-earth-element
enrichment, and hosted in granite. Major constituents of the
pegmatite are
quartz, perthite,
cleavelandite, iron oxides and
biotite. Accessory minerals include fluocerite,
bastnäsite, columbite,
cyrtolite and minor uranium-thorium species. Well developed tabular crystals
of fluocerite are epitaxially overgrown by bastnäsite, and occur in a matrix of irone-oxide boxwork associated
with quartz crystals. The
bastnäsite overgrowth is
zoned with respect to rare-earth elements and exhibits linear bands of enrichment in
neodymium, samarium,
gadolinium and yttrium.
The fluocerite-bastnäsite crystals
appear to be late in the paragenesis
(R&M 91-4.371-373).
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