Aragonite is a carbonate mineral, one of the two common, naturally occurring polymorphs of calcium carbonate, CaCO3. The other polymorph is the mineral calcite. Aragonite’s crystal lattice differs from that of calcite, resulting in a different crystal shape, an orthorhombic system with acicular crystals. Repeated twinning results in pseudo-hexagonal forms.
|Carbonate||White, red, yellow, orange, green, purple, grey, blue and brown|
|CaCO3||Vitreous, resinous on fracture surfaces|