Selenite

Sample of brown/orange arrowhead shape euhedral Selenite with beveled edges entwined with thin, colourless prismatic euhedral Quartz crystals that have a vitreous lustre. Average Selenite size: 0.7 cm x 0.7 cm x 0.1 cm. Average Quartz size: 1.6 cm x 0.1 cm x 0.2 cm. Selenite is the colourless variety of Gypsum (CaSO4 x 2H2O) that can also be brownish or reddish tints. Lustre is vitreous and pearly along the cleavage surfaces and steak is white. Hardness is 1 1/2 to 2 and cleavage is perfect in one direction and distinct in two other directions. Gypsum can be untwinned single crystals, rhombic form, twinned with an arrowhead shape with beveled edges, granular, massive, earthy or fibrous.