From Conservapedia
Calcite is made of
calcium carbonate (CaCO3). Generally
white to
clear, it is easily scratched with knife. Calcite is number 3 on the
Mohs Hardness Scale. Most
seashells are made of calcite or related minerals. This is the 'lime' of
limestone.
[1]
References
- ↑ http://wrgis.wr.usgs.gov/docs/parks/rxmin/mineral.html#amphibole