Aragonite
Formula:CaCO3
Colour:Colorless to white or grey, often stained various hues by impurities, such as blue, green, red or violet; colourless in transmitted light.
Classification:Carbonates
Lustre:Vitreous, Resinous
Crystal System:Orthorhombic
Hardness:3.5-4
Specific Gravity:2.9-3