Search results
Results from the WOW.Com Content Network
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 ...
Ikaite is the mineral name for the hexahydrate of calcium carbonate, CaCO 3 ·6H 2 O.Ikaite tends to form very steep or spiky pyramidal crystals, often radially arranged, of varied sizes from thumbnail size aggregates to gigantic salient spurs.
The minerals that accompany them are calcite, epidote, vesuvianite, garnet, wollastonite, diopside and amphibole. The scapolites are colorless, flesh-colored, grey or greenish; occasionally they are nearly black from the presence of very small enclosures of graphitic material.
Cave pearls form when water dripping into a cave loses carbon dioxide and precipitates calcite. A cave pearl forms when the water is moving too vigorously to form a stalagmite . A nucleus of matter (such as a grain of sand ) becomes coated with calcite , and the current then provides a rotation to the nucleus in such a way that it is coated evenly.
As a type of calcite, Iceland spar can be used in construction as a building material in cement and concrete. Its high purity and brightness make it an ideal filler in paints and coatings. [ 54 ] In metallurgy, calcite acts as a flux to lower the melting point of metals during smelting and refining. [ 55 ]
Photomicrograph of a thin section in cross and plane polarised light: the brighter mineral grains in the picture are dolomite, and the darker grains are calcite. Dolomite ( / ˈ d ɒ l . ə ˌ m aɪ t , ˈ d oʊ . l ə -/ ) is an anhydrous carbonate mineral composed of calcium magnesium carbonate , ideally CaMg(CO 3 ) 2 .
Because coccoliths are formed of low-Mg calcite, the most stable form of calcium carbonate, they are readily fossilised. They are found in sediments together with similar microfossils of uncertain affinities (nanoliths) from the Upper Triassic to recent. They are widely used as biostratigraphic markers and as paleoclimatic proxies.
The term caliche is borrowed from Spanish and is originally from the Latin word calx, meaning lime. [1] Caliche is generally light-colored but can range from white to light pink to reddish-brown, depending on the minerals present. Caliche is a mark of older landscapes. It generally occurs on or very near the surface.