Calcite (sparry) (Iceland Spar)CaCO3
Class: Carbonate Hardness: 3 Density: 2.7 Streak: White Lustre: Vitreous Habit: Large crystals, some exhibiting common twin striae Colours: White | | Crystal System: Hexagonal Cleavage: Perfect rhombohedral Fracture: Subconchoidal Magnetism: None Reaction with HCl: Strong | Identification in hand sample: Hardness, crystal habit and twin striae are typical. Associations: Common as a cementing agent in clastic sediments or as fossil fragments. Industrial / ecomonic uses: Used in the manufacture of portland cement (quicklime) and in the pharmaceutical industry. Comments: The transparent variety is called "Iceland Spar". |