Aragonite

Three samples of reddish/brown short pseudo-hexagonal prismatic euhedral Aragonite crystals. Resinous to vitreous lustre. Largest crystal size: 2.7 cm x 0.9 cm x 0.9 cm. Aragonite (CaCO3) can be white, grey, colourless, yellow, pale green, violet, red or brown. Lustre is 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 others. Aragonite usually occurs as short or long prismatic crystals but can also be fibrous acicular, columnar, stalactitic aggregates or twinned crystals that shows pseudo hexagonal prisms and spear-or chisel shaped forms.