How can you identify gypsum

Varieties of gypsum known as "satin spar" and "alabaster" are used for a variety of ornamental purposes; however, their low hardness limits their durability. Gypsum wallboard and plaster: Wallboard and construction plaster are the primary industrial uses of gypsum in the United States. Alabaster Gypsum: Alabaster, a variety of gypsum, from Pomaia, Italy.

Specimen is approximately 3 inches 7. Gypsum translucency: The translucent characteristic of alabaster, a variety of gypsum, from Pomaia, Italy. The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Inexpensive mineral collections are available in the Geology. Satin spar Gypsum: Satin spar, a fibrous variety of gypsum from Derbyshire, England.

An agricultural soil treatment. Find Other Topics on Geology. Maps Volcanoes World Maps. Feel both pieces of rock for how slippery they are.

If the rock is slippery, it may be talc. Fragment pieces of each rock with your fingernail. If cleavage fragments fall off and are tiny, the specimen is talc. Cleavage on talc is perfect. Cleavage is the quality of a split along defined planes of a rock or mineral. In this case, you would be splitting the rock with your fingernail. Scratch each piece of rock. Check the colors of each.

There are also two poor cleavages that can be seen in three of the four samples shown here. These give the fragments a skewed angular look. This is also seen in the photo above.

These show the typical shape of well-formed selenite crystals. The brownish color comes from impurities incorporated by the crystals as they grew just under a soil surface. This 3-cm disk of selenite with brownish impurities has a biconvex cross section like a lens. Note the potential cleavage planes running from the upper right to lower left.