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Mineral

Calcite

Carbonate Minerals

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate, CaCO3; the other polymorphs are aragonite and vaterite. It is a very common mineral, a major constituent of limestone, the primary mineral in metamorphic marble, and often the main constituent of the shells of marine organisms. Calcite defines hardness 3 on the Mohs scale and has a vitreous luster in crystals. It is white or colorless unless impurities tint it gray, red, orange, yellow, green, blue, violet, brown or black. It fizzes in acid, and groundwater can dissolve or precipitate it, which is how stalactites and stalagmites form in caves. A transparent variety called Iceland spar shows strong birefringence, so objects seen through it appear doubled, and large calcite crystals are used in optical equipment.

Facts
Formation Class
Carbonate mineral 1
Chemical Formula
CaCO3, calcium carbonate 1
Hardness (Mohs)
3 1
Calcite is the reference mineral that defines the value of 3 on the Mohs scale itself.
Colour
Colourless or White 4
Colour
Grey or Black 4
Colour
Brown 4
Colour
Red or Pink 4
Colour
Orange or Yellow 4
Colour
Green 4
Colour
Blue or Purple 4
Lustre
Vitreous 4
Rarity
Common 4
Classification
Strunz Class
Carbonates and Nitrates 1
Crystal System
Trigonal (Rhombohedral) 2
Use
Sculpture and Ornamental 3
Wikipedia 'Calcite' states this use (or use-bearing statement); earth5 pass.
Connections

Associated With

Evaporite, Materials

Calcite named as one of the most common marine evaporite minerals; cited via evaporite's own registered source since Calcite carries only the generic mineral-wikipedia stub as its own source.

Source Evaporite (Wikipedia)
Skarn, Materials

Skarn typically forms from a carbonate (limestone or marble) protolith, and calcite persists in many skarns.

Caused By

Biomineralization, Processes
Source Calcite (Wikipedia)
Diagenesis, Processes
Source Calcite (Wikipedia)
Hydrothermal Circulation, Processes
Source Calcite (Wikipedia)
Hydrothermal Mineral Deposition, Processes
Source EBSCO Research Starters: Hydrothermal solutions and mineralization
Metamorphism, Processes
Source Calcite (Wikipedia)
Sedimentation, Processes
Source Calcite (Wikipedia)

Classified As

Carbonate Minerals, Subcategories

Crystallizes In System

Trigonal Crystal System, Concepts

In Discipline

Mineralogy, Disciplines
Source Mineral (Wikipedia)
In the Other Atlases

Mineral Species Of

Calcite

Also in Divinity Atlas: of this mineral species.

Green Calcite

Also in Divinity Atlas: of this mineral species.

Sources
1. Mineral (Wikipedia)
Wikimedia FoundationLead section
Quote, Lead section
The reaction of acid with carbonates, most commonly found as the polymorph calcite and aragonite (CaCO3), relates to the dissolution and precipitation of the mineral, which is a key in the formation of limestone caves, features within them such as stalactite and stalagmites, and karst landforms.
View the Source
2. Calcite (Wikipedia)
  • Lead section
    Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison.
  • Infobox: system
    Trigonal
  • Caused By: Sedimentation, Natural occurrence
    Calcite is a common constituent of sedimentary rocks, limestone in particular, much of which is formed from the shells of dead marine organisms.
  • Caused By: Biomineralization, Natural occurrence
    Calcite is often the primary constituent of the shells of marine organisms, such as plankton (such as coccoliths and planktic foraminifera), the hard parts of red algae, some sponges, brachiopods, echinoderms, some serpulids, most bryozoa, and parts of the shells of some bivalves (such as oysters and rudists).
  • Caused By: Diagenesis, Natural occurrence
    Bedding parallel veins of fibrous calcite, often referred to in quarrying parlance as beef, occur in dark organic rich mudstones and shales, these veins are formed by increasing fluid pressure during diagenesis.
  • Caused By: Metamorphism, Natural occurrence
    It is the primary mineral in metamorphic marble.
  • Caused By: Hydrothermal Circulation, Natural occurrence
    It also occurs in deposits from hot springs as a vein mineral; in caverns as stalactites and stalagmites; and in volcanic or mantle-derived rocks such as carbonatites, kimberlites, or rarely in peridotites.
View the Source
3. Wikidata: Calcite
Wikidata Q171917
4. minerals.net: Calcite
minerals.net
  • Color field
    Colorless, white, yellow, brown, orange, pink, red, purple, blue, green, gray, black. May also be multicolored or banded.
  • Luster field
    Vitreous
  • Description
    Calcite is the one of the most common minerals.
View the Source
Evaporite (Wikipedia)
Wikimedia FoundationAssociated With: Evaporite, Marine evaporite minerals section
Quote, Associated With: Evaporite, Marine evaporite minerals section
The most common marine evaporites are calcite, gypsum and anhydrite, halite, sylvite, carnallite, langbeinite, polyhalite, and kainite.
View the Source
EBSCO Research Starters: Hydrothermal solutions and mineralization
EBSCO Research StartersCaused By: Hydrothermal Mineral Deposition, Hydrothermal deposit types and gangue minerals
Quote, Caused By: Hydrothermal Mineral Deposition, Hydrothermal deposit types and gangue minerals
Calcite, fluorite, and barite are also common as gangue minerals.
View the Source
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