Calcite is transparent but gives a double image of things when you look through it. Usually it is colorless to white. It can also have a combination of colors, due to impurities, like blue and black. Pink or red calcite, usually named cobaltocalcite is made into beautiful items. The white, fibrous variety of calcite is cut into cabochons for jewelry to show the cat’s-eye effect. Another variety is the Iceland spar, which is found in lava cavities in Iceland, it is colorless and transparent.
It is usually found worldwide in limestone rocks, but especially in Austria, Germany, France, United Kingdom, Iceland, Ireland, Mexico, United States (in New York State, Ohio, Michigan, Illinois, Missouri, North Dakota, Montana, Franklin, New Jersey and Cochise County, Arizona). In Canada major calcite deposits include Cobalt, Timiskaming County, Ontario.