GypsumGypsum has a very low thermal conductivity (hence its use as an insulating filler). A crystal of gypsum will feel noticeably warmer than, for instance, a crystal of quartz. Gypsum is one of the more common minerals in sedimentary environments. It is a major rock forming mineral that produces massive beds, usually from precipitation out of highly saline waters.
Chemical composition - CaSO
Other specimens - Click the thumbnails to enlarge