Colour: white when almost pure. Due to admixtures, limestone can appear in all shades. Limonite and siderite produce yellow and brown tones, haematite reddish tones, glauconite and chlorite greenish tones, whilst bitumen and carbonaceous components produce grey to almost black colours. Limestone consists essentially of a single mineral, namely calcite. Minor constituents include dolomite, siderite, quartz, feldspars, mica and clay minerals. The texture of limestone is compact or porous, fine- or coarse-grained, and, with the exception of reef formations, always layered. Limestone is highly vulnerable to flue gas.

Formation:

Deposited layers of calcareous mud solidify.

Locations:

The Kalkalpen, the Franconian, Swabian, Swiss and French Jura, Rügen, Denmark (Mön), England (Dover), USA (New Mexico)

Products:

Limestone is used as road ballast and grit, in cement production, as building blocks and decorative slabs, in sugar manufacture, in the production of glass and paints, as an additive in the smelting of iron ores, and as a fertiliser.