Liebigite

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Liebigite
Liebigite-171838.jpg
Liebigite crystals from the Ralston Buttes District, Jefferson County, Colorado
General
CategoryCarbonate mineral
Formula
(repeating unit)
Ca2(UO2)(CO3)3·11H2O
Strunz classification5.ED.20
Crystal systemOrthorhombic
Crystal classPyramidal (mm2)
(same H-M symbol)
Space groupBba2
Unit cella = 16.699, b = 17.557
c = 13.697 [Å]; Z = 8
Identification
ColourGreen to yellowish-green
Crystal habitRare as short prismatic crystals; scaly or granular, in aggregates, crusts, and films
CleavageDistinct on {100}
TenacityBrittle
Mohs scale hardness2 12 - 3
LustreVitreous, pearly
DiaphaneityTransparent, translucent
Specific gravity2.41
Optical propertiesBiaxial (+)
Refractive indexnα = 1.497 nβ = 1.502 nγ = 1.539
Birefringenceδ = 0.042
PleochroismVisible: X = nearly colourless Y = Z = light yellowish green
2V angle37° to 42°
Ultraviolet fluorescenceStrong green to blue-green under short and long wave UV
References[1][2][3]

Liebigite is a uranium carbonate mineral with the chemical formula: Ca2(UO2)(CO3)3·11H2O. It is a secondary mineral occurring in the oxidizing zone of uranium-bearing ores. It is green to yellow green in colour. It has a Mohs hardness of about 3. Liebigite, like some other uranium minerals, is fluorescent under UV light and is also translucent. It crystallizes in the orthorhombic system, but only rarely forms distinct crystals. It typically forms encrustations or granular aggregates.[1][2][3]

It was first described in 1848 for an occurrence in Adrianople, Edirne Province, Marmara Region, Turkey.[1] It was named for German chemist Justus von Liebig (1803–1873).[3]

References[edit]