Carbonate identification and genesis as revealed by staining

A staining procedure consisting of preliminary etching with dilute hydrochloric acid, treatment with a mixed solution of alizarin red-S and potassium ferricyanide, and a final treatment with alizarin red-S alone (Dickson, 1965) permits the distinction of orthorhombic carbonates and of calcite from other trigonal carbonates. The potassium ferricyanide stain reveals the distribution of iron in both calcite and dolomite. The use of the stains is illustrated by a discussion of the petrography of selected specimens and interpretations of the origin of various petrographic entities.