Calcite

Numerous small euhedral scalenohedrons Calcite crystals that are colourless with a dull lustre. Average crystal size: 1.3 cm x 0.4 cm x 0.3 cm. Calcite (CaCO3) can be white, colourless or be pale shades of grey, yellow, red, green, blue and brown or black when impure. Lustre is vitreous or dull and streak is white. Hardness is 3 and cleavage is perfect in three directions and forms a rhombohedron. Calcite is usually found as rhombohedrons or scalenohedrons but can be found as prisms, tabular, cleavable, granular, acicular, compact, stalactitic, oolitic or earthy in form.