Calcite

Formula: CaCO3
Colour: White, Yellow, Red, Orange, Blue, Green, Brown, Gray etc.
Lustre: Vitreous, Sub-Vitreous, Resinous, Waxy, Pearly
Hardness:   3
Specific Gravity: 2.7102
Crystal System: Trigonal
Name: Ancient name. Named as a mineral by Gaius Plinius Secundus (Pliny the elder) in 79 from Calx, Latin for Lime.