The name aragonite comes from the locality of Aragon, Spain where the first pseudohexagonal twins of aragonite were recognized. Aragonite is a polymorph of calcite (they have the same chemistry, but different structures), but is both harder and has a higher specific gravity. Aragonite forms as higher pressures and lower temperatures than calcite.
| CaCO3 |
|
| Carbonate |
|
| Orthorhombic |
|
| 2/m 2/m 2/m |
|
| 3.5-4 |
|
| 2.94 |
|
| {010} distinct, {110} poor |
|
| Subconchoidal |
|
| Colorless, white, pale yellow, various tints |
|
| White |
|
| Vitreous |
|
| Transparent/translucent |
|
| Columnar, fibrous |
|
| Notable Localities: |
Aragon, Spain; Girgenti, Sicily, Italy; Bilina, Czechoslovakia; Cumbria, England; Styria, Austria; Baja California, Mexico; Arizona and New Mexico |
| Uses: |
Mineral specimen |
Specimens:
| |
