Calcite occurs in more crystal formations than any other mineral. Crystal size and shape varies greatly.
It can be found in almost any colour. Calcite is a soft mineral so must be handled carefully.
It can demonstrate double refraction of light. This means when light passes through, the crystal splits in two creating a double image.
One of the most common minerals on Earth, calcite forms many rock types. It can also be found in caves as stalagmites and stalactites.