The following excellent article on the origins of dolomite published by Forbes explains dolomite in detail.

The Dolomites are the only mountainous region named in historic times after a mineral and not, as usual, the other way round.

Dolomite was first described as mineral in 1792 by Swiss naturalist Nicolas de Saussure. As a peculiar type of limestone, however, it was already known. Miners named the dolostone “Bitterspat” and “Murakalzit,” due to its similarities to real limestone, which is composed mostly of the mineral calcite. Physician and botanist Carl Linnaeus, who introduced the modern classification system for animals and plants and the binomial nomenclature, called it “Marmor tardum,” in reference to the weak reaction of its crystals with acid. However, nobody had considered that the rock was composed by a new, unknown mineral.