M840 -
Selenite Crystals (Utah).
Selenite is a gypsum material used as a plaster and in
cement. Selenite is a Hydrous calcium sulfate. Hardness 1-1/2 to 2. Can
be scratched with your fingernail. Gypsum is a very common sulfate
mineral. Although it may be found in several rock types, it develops
principally in sedimentary rocks of chemical origin, where it forms rock
gypsum deposits in the beds that may be up to 30 feet in thickness. It
also occurs associated with dolomite and barite in hydrothermal
replacement deposits.
From
Utah.
Price: $
2.20 each
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