Aragonite
| Aragonite | |
|---|---|
 Aragonite frae Salsignes Mine, Aude department, France Size: 30x30x20 cm | |
| General | |
| Category | Carbonate mineral |
| Formula (repeatin unit) | CaCO3 |
| Strunz clessification | 05.AB.15 |
| Creestal seestem | Orthorhombic |
| Space group | Orthorhombic (2/m 2/m 2/m) - dipyramidal |
| Unit cell | a = 4.95 Å, b = 7.96 Å, c = 5.74 Å; Z = 4 |
| Identification | |
| Colour | White, reid, yellae, orange, green, purpie, grey, blae an broun |
| Creestal habit | Pseudohexagonal, prismatic crystals, acicular, columnar, globular, reniform, pisolitic, coralloidal, stalactitic, internally bandit |
| Twinnin | Polysynthetic parallel tae {100} cyclically on {110} |
| Cleavage | Distinct on {010}, imperfect {110} an {011} |
| Fractur | Subconchoidal |
| Tenacity | Brickle |
| Mohs scale haurdness | 3.5-4 |
| Skinkle | Vitreous, resinous on fracture surfaces |
| Streak | White |
| Diaphaneity | Leamin tae skyre |
| Speceefic gravity | 2.95 |
| Optical properties | Biaxial (-) |
| Refractive index | nα = 1.529 - 1.530 nβ = 1.680 - 1.682 nγ = 1.685 - 1.686 |
| Birefringence | δ = 0.156 |
| 2V angle | 18° |
| Solubility | Dilute acid |
| Ither chairacteristics | Fluorescence: fauch rose, yellae, white or blaeish; phosphorescence: greenish or white (LW UV); yellaeish (SW UV) |
| References | [1][2][3] |
Aragonite is a carbonate mineral, ane o the twa common, naiturally occurrin, crystal furms o calcium carbonate, CaCO3 (the ither furm bein the mineral calcite). It is furmed bi biological an pheesical processes, includin precipitation frae marine an freshwatter environments.
Aragonite's crystal lattice differs frae that o calcite, resultin in a different crystal shape, an orthorhombic seestem wi acicular crystals. Repeatit twinnin results in pseudo-hexagonal furms. Aragonite mey be columnar or fibrous, occasionally in branchin stalactitic furms cried flos-ferri ("flouers o airn") frae thair association wi the ores at the Carinthian airn mines.