DOLOMITE or DOLOSTONE
Dolomite (or Dolostone) is an evaporative sedimentary rock consisting primarily of the mineral dolomite (calcium magnesium carbonate). Since dolomite is less water soluble than calcite, it precipitates first and is also more stable when water containing magnesium penetrates a limestone, resulting in the gradual conversion of a limestone bed into a dolomite bed.
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