Aragonite

Sample of reddish/colourless subhedral prismatic Aragonite crystals that are radiating aggregates. Lustre is vitreous. Largest Aragonite crystal size: 1.6 cm x 0.9 cm x 0.7 cm. Aragonite (CaCO3) can be white, red, grey, colourless, yellow, pale green, violet or brown in colour. Lustre can be vitreous or resinous and streak is white. Hardness is 3 1/2 to 4 and cleavage is good in one direction and poor in two other directions. Aragonite usually occurs as prismatic crystals that are short or long but can also be fibrous acicular, columnar or stalactitic aggregates.