Andersonite

Andersonite, Andersonit or Andersonita (Na2CaUO2(CO3)3-6H2O), or hydrated sodium calcium uranyl carbonate is a rare uranium carbonate mineral, that was only described in the last half century. Named for Charles Alfred Anderson (1902-1990) of United States Geological Survey, who first described the mineral species, it is found in sandstone-hosted uranium deposits. It has a high vitreous to pearly luster and is very fluorescent. Andersonite specimens will usually glow a bright lemon yellow (or green with blue hints depending on the deposit) in ultraviolet light. The mineral is formed as a secondary mineral and as an efflorescent crust in uranium mines. It is commonly found as translucent small rhombohedral crystals that have angles close to 90 degrees although its crystal system is nominally trigonal Its Mohs hardness is 2.5, with an averageSpecific Gravity of 2.9.
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General Information:
 Chemical Formula:
Na2Ca(UO2)(CO3)3·6(H2O)
 Composition:
(Molecular Weight = 644.20 gm)
Sodium 7.14 % Na
Calcium 6.22 % Ca
Uranium 36.95 % U 
Hydrogen 1.88 % H 
Carbon 5.59 % C 
Oxygen 42.22 % O 
 Empirical Formula:
Na2Ca(UO2)(CO3)3·6(H2O)
 Environment:
Sandstone-hosted uranium deposits.
 Locality:
Hillside mine, Bagdad, Yavapai County, Arizona, USA.
 Name Origin:
Named for Charles Alfred Anderson (1902-1990), U. S. Geological Survey.
Physical Properties:
 Color:
bright yellow green or green.
 Density:
2.79 - 2.87, Average = 2.83
 Diaphaniety:
Transparent to Translucent
 Habits:
Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces., Rhombohedral Crystals - Occurs as well-formed crystals showing rhobohedral crystals., Pseudo Cub ic - Crystals show a cubic outline.
 Hardness:
2.5 - Finger Nail
 Luminescence:
Fluorescent, Short UV=bright yellow green, Long UV=bright yellow green.
 Luster:
Vitreous - Pearly
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