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Minerals A-E
Calcite
Name
Calcite
Chemistry
CaCO3, Calcium Carbonate
Uses
As a specimen and in cements and mortars, production of lime, limestone is used in the steel industry; glass industry, ornamental stone, chemical and optical uses And as a whitener in paints.
Color
Different shades of soft pink, yellow, white, brown,
Hardness
3
Specific gravity
2.7
Calcite has double refraction effect (when a clear crystal is placed on a single line, two lines can then be observed) It effervesces easily with dilute acids and may be fluorescent or phosphorescent.
Calcite is the most common of the carbonate minerals and one of the most common and widely distributed of all minerals. It is the only form of calcium carbonate that is fully stable at Earth-surface conditions, although two other polymorphs, aragonite and vaterite, are known to form under certain conditions.
Calcite occurs in virtually all geologic settings: as a primary igneous mineral in carbonatite and kimberlite; in metamorphic form as marble; as a common mineral in hydrothermal ore deposits; and as a common secondary mineral, filling fractures and cavities. The pure, optically clear variety named Iceland spar, found in cavities in basalt, displays an extreme form of birefringence known as double refraction. The most abundant and important occurrences, however, are in sedimentary rocks, where biogenic calcite, derived from the remains of calcareous marine organisms, is the principal constituent of limestone.
Calcite is deposited as travertine in springs and in the fresh water of caves.
Calcite limestones and marbles are used as building and ornamental stones; limestone is used as a road stone, in the production of cement, as a flux in steel smelting, and for agricultural lime. Natural and precipitated calcite is an ingredient of such commodities as toothpaste, antacids, chewing gum, rubber, food fillers, glue, and soap, and is also the main source of calcium for the chemical industry.
