aragoniiitti
Aragoniiitti, known in English as aragonite, is a carbonate mineral and one of the two common polymorphs of calcium carbonate (CaCO3), the other being calcite. It crystallizes in the orthorhombic system and tends to form slender, prismatic, tabular, or needlelike crystals, often in fibrous or radiating aggregates. The mineral is typically colorless or white, but impurities can produce a range of colors.
Occurrence and formation. Aragonite occurs in both biogenic and abiogenic environments. It is a major component
Stability and transformation. At standard Earth surface conditions, aragonite is metastable relative to calcite and can
Properties and significance. Aragonite has a hardness around 3.5–4 on the Mohs scale and a specific gravity