Aragonite
Aragonite is often found in caves and can be found in South Africa, Namibia and Zimbabwe. Many stalactites and stalagmites are composed of aragonite and when unstable may convert to calcite. Aragonite usually forms smooth but botryoidal masses referred to as flowstone. Aragonite can be pyramidal, tabular or acicular forming long hair like crystals. it forms in Yellow, green, brown or white.
Chemical Formular : CaCO3
Refractive Index : 1.525 to 1.686
Hardness :3½ – 4 on the Mohs Scale
Crystal System :Orthorhombic