Roger Weller, geology instructor
[email protected]
copyright 2006-R.Weller
Mineral
Information on:
aragonite
Chemical Group:
carbonate
Chemical Formula:
CaCO3
Color: white, gray, yellow, green, pink, red, violet
Streak: white
Transparency: transparent to translucent
Hardness: 3.5 to 4
Specific Gravity: 2.93 to 2.95
Fracture: subconchoidal
Luster: vitreous to resinous
Cleavage: two directions
Crystal Forms and habits:
Orthorhombic system
Aragonite is commonly acicular (see cave formations).
Another common form is a pseudo-hexagonal plate
produced by twinning.
Mineral Associations:
Identifying Characteristics: Fizzes with hydrochloric like calcite
Uses:
Occurrences: Bisbee, Arizona (acicular) and Ft. Collins, Colorado
(hexagonal twins)
Toxicity: when-swallowed- low
when inhaled- low
Additional Information: Aragonite is less stable than calcite and will
often revert to calcite.