1. n. [Geology]

A rock composed chiefly (> 90%) of dolomite. The rock is sometimes called dolomite, but dolostone is preferable to avoid ambiguity between the mineral and rock names. Replacement dolomite that forms soon after deposition is typically fine-grained and preserves original sedimentary structures. Recrystallization late in diagenesis produces coarser grained dolomite, destroys sedimentary structures and results in higher porosity.

See: carbonate,  diagenesis,  dolomite,  dolomitization,  evaporite