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Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO 3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed ...
Smoky quartz with spessartine on top of feldspar matrix, featuring different crystal habits (shapes). In mineralogy, crystal habit is the characteristic external shape of an individual crystal or aggregate of crystals.
Calcite is part of WikiProject Rocks ... It can be in the crystal system of trigonal in the class of hexagonal scalenohedral. ... Calcite is a stable mineral, meaning ...
In the hexagonal family, the crystal is conventionally described by a right rhombic prism unit cell with two equal axes (a by a), an included angle of 120° (γ) and a height (c, which can be different from a) perpendicular to the two base axes.
Calcite rhombohedral crystal structure. Iceland spar is a colourless, transparent variety of calcium carbonate (CaCO 3). [3] It crystallizes in the trigonal system, typically forming rhombohedral crystals. [4]
Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO 3.In its pure form (rare), it is typically a rose-red colour, [5] but it can also be shades of pink to pale brown.
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Dogtooth spar with fluorite from the Elmwood Mine in Tennessee. Spar is an old mining or mineralogy term used to refer to crystals that have readily discernible faces. A spar will easily break or cleave into rhomboidal, cubical, or laminated fragments with smooth shiny surfaces.