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Formula: Sr(UO2)2(V2O8).5H2O
Vanadate,
francevillite group,
uranyl mineral, strontium-bearing
mineral
Crystal System: Orthorhombic
Specific gravity: 4.352 calculated
Hardness: 2
Streak: Light yellow
Colour: Golden yellow
Luminescence: No fluorescence under UV
Solubility: Relatively insoluble in water
RADIOACTIVE
Environments
Sedimentary environments
Hydrothermal environments
Finchite is the first uranium mineral known to contain essential
strontium. It is a possible immobilisation species for both
uranium and the dangerous radionuclide 90Sr because of the
relative insolubility of uranyl
vanadate minerals in water
(AM 108.2.383-388).
Localities
There are two co-type localities, the Sulfur Springs Draw, Lamesa, Martin County, Texas, USA, and the Pandora Mine,
La Sal Mining District, San Juan County, Utah, USA.
At the Globe Hill Mine, Globe Hill, Cripple Creek Mining District, Teller County, Colorado, USA, finchite
crystals occur in an extensively hydrothermally altered felsic
volcanic igneous rock
(phonolite or
trachyte?), associated with
celestine, fluorite and
iron oxides. Platey crystals up to 3 mm occurred in some samples of the rock.
The original locality is apparently no longer accessible, as it was reportedly filled in during subsequent mining
operations
(Mindat).
Finchite from Globe Hill - Image
At the Sulfur Springs Draw, Lamesa, Martin County, Texas, USA, finchite occurs as yellow-green blades up to
~10 µm in length in surface outcrops of the calcrete-type
uranium deposit
(AM 108.2.383-388).
Associated minerals include quartz,
illite, dolomite,
celestine and carnotite
(Mindat).
Finchite from Sulfur Springs - Image
At the Pandora Mine, La Sal Mining District, San Juan County, Utah, USA, crystals of finchite were discovered
underground as diamond-shaped golden-yellow crystals reaching up to 1 mm
(AM 108.2.383-388).
Associated minerals include pandoraite-Ca
(HOM).
Finchite from the Pandora Mine - Image
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