Gypsum

Sample is of "Desert Rose" Gypsum. Colour is yellow to brown with a vitreous lustre and crystal habitat is beveled arrowheads. Gypsum (CaSO4 x 2H2O) can be white, colourless, grey, yellow, red or brown in colour. Lustre is vitreous and pearly on the cleavage surfaces. Streak is white and hardness is 1 1/2 to 2. Cleavage is perfect in one direction and distinct in two other directions. Gypsum usually occurs as single untwinned rhombic crystals but can also occurs as twinned crystals that form an arrowhead shape with beveled edges, granular, massive, fibrous (Satin Spar) or earthy. Smallman Collection