Calcite, CaCO3 (Calcium Carbonate), is one of the commonest minerals, being the main constituent of limestone. Calcite is often fluorescent, a small amount of Managnese is enough to make it glow red under UV light. The mineral will bubble in acid distinguishing it from many similar species, even other carbonates which do not dissolve so easily in cold acids.

Description: A small elongated specimen covered by an interesting Calcite mineralisation. At least three different crystal habits are present, including small dog-tooth, tetrahedral and stalactitic forms. The colour is creamy white. Amongst the Calcite lie one or two Biotite mica plates.

Location: Kamaresa Mine, Laurion, Greece.