| Mineral | ARAGONITE |
| Chemistry | CaCO 3 |
| Class | Carbonates |
| Uses | minor constituent of limestone which is used in cement and in steel production, ornamental carvings and as mineral specimens. |
| Color | Colorless to white or greyoften stained various hues by impuritiessuch as blue Green red or violet. |
| Luster | VitreousResinous |
| CrystalSystem | Orthorhombic |
| CrystalHabits | include twinned hexagonal prismatic crystals as well as a diverse assortment of thin elongated prismatic, curved bladed, steep pyramidal (spiked) and chisel shaped crystals. A branching tree, coral or worm-like delicate form is called flos ferri . Can also be compact, granular, radially fibrous and massive. Its massive forms can be layered, coralloid, pisolitic, oolitic, globular, stalachtitic and encrusting.Aragonite is a constituent of many species shell structures.A layered sedimentary marble like formation is called Mexican Onyx and is used for carvings and ornamental purposes.Calcite pseudomorphs of aragonite crystals and formations are common. |
| Cleavage | Distinct/Good Distinct on {010} |
| Fracture | distinct in one direction (pinacoidal). |
| Hardness | 3½ - 4 |
| SpecificGravity | 2.944 g/ccm |
| Streak | Uncolored/white. |
| AssociatedMinerals | As speleothems in limestone caves; as pisolitessinters and massive lamellar deposits at geysers and hot springs; as seafloor oolites; with siderite in iron deposits; with calcite and dolomite and other magnesium minerals in altered serpentinitesdunites and peridotites; and as a replacement mineral in various rock types and ore depositsformed from low-temperature and pressure aqueous solutions. |
| Characteristics | aragonite effervesces easily in cold dilute hydrochloric acid, is strongly birefringent, is fluorescent and its refractive index is 1.7 . |
| Occurences | include Aragon, Spain (its type locality and from where it gets its name); Morocco; Bastennes, France; Girgenti, Sicily; Alston Moor and Cleator Moor, Cumberland, England; Baja California, Mexico (Mexican Onyx); Tsumeb, Namibia; Carinthia, Austria; Leadhills, Scotland; Harz Mountains, Germany and in several localities in the Southwestern United States. |
| Indicators | crystal habits, single plane of cleavage and reaction to acid. |
| DensityNote | average for non-metallic minerals |
| IMAStatus | Approved |
| Discovered | 1797 |
| CellParameters | a = 4.95b = 7.96c = 5.74 |
| Ratio | a:b:c = 0.622 : 1 : 0.721 |
| OpticalType | Biaxial (-) |
| RI | n α =1.529 - 1.530 n β =1.680 - 1.682 n |
| Birefringence | δ=0.156 |
| SurfaceRelief | High |
| TypeLocality | Molina de Aragón Guadalajara Castile- La Mancha Spain |
| Strunz | 5/B.04-10 5 : NitratesCarbonates & Borates B : Waterfree carbonates without unfamiliar anions 04 : Aragonite group |
| FolkLore | Said to be helpful in centering yourself, especially during times of stress and anger. Said to enhance patience. |
