In large masses, the mineral forms the rock called dolomite. It may be white, gray, greenish gray, brown, or pink, and it has a glassy to pearly luster.
Dolomite is slightly harder than calcite, although it can easily be scratched by a knife.
It will not fizz readily in dilute solutions of cold hydrochloric acid unless first ground to a powder. The sample pictured above is from Cherokee County, Kansas.