Calcite

Sample of white rhombohedron subhedral Calcite crystals compact together. Vitreous lustre. Average crystal size: 0.8 cm x 0.6 cm 0.5 cm. Calcite (CaCO3) can be white, colourless or pale shades of grey, yellow, red, green or blue but can also be brown or black from impurities. Lustre is vitreous or dull and streak is white. Hardness is 3 and cleavage is perfect in three directions forming a rhombohedron. Calcite usually occurs as rhombohedron or scalenohedron but can also be prismatic, tabular, acicular, cleavable, granular, compact, stalactitic or oolitic.