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: An unusual specimen of Calcite showing stepped crystal faces resulting from successive growth zones. Consequently the largest crystal is actually triply terminated, each growing from a separate point of origin. A very unusual effect.

Location: Tudorow, Poland.