Scientific Name: Calcium carbonate

Group: Carbonates

Chemical composition: CaCO3

Colors: sky blue

Hardness: 3.5 to 4

Formation: Elongated prismatic crystals.

Principal Sources: Czech Republic, Mexico, Austria, Greece, Morocco, England, France, Germany, Italy, Hungary, Japan, USA

Special Notes: Forms in metamorphic and sedimentary rocks, often near hot springs. Crystals often twin creating “Flos Ferri” or “flowers of iron.” Argentinian aragonite is a deep tangerine orange with white frothy inclusions.