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Hematite. Hematite (/ ˈhiːməˌtaɪt, ˈhɛmə -/), also spelled as haematite, is a common iron oxide compound with the formula, Fe 2 O 3 and is widely found in rocks and soils. [6] Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of Fe. 3.
In scientific usage, shungite refers to a mineraloid which contains >98% carbon, and is used as a modifier to the host-rock's name, i.e. "shungite-bearing dolostone". [10] In popular usage, shungite-bearing rocks are sometimes themselves referred to as shungite. Shungite is subdivided into bright, semi-bright, semi-dull and dull on the basis of ...
The mineral aggregate heliotrope (from Ancient Greek ἥλιος (hḗlios) 'sun' and τρέπειν (trépein) 'to turn'), also called Indian bloodstone or ematille, is a cryptocrystalline mixture of quartz that occurs mostly as jasper (opaque) or sometimes as chalcedony (translucent). The "classic" bloodstone is translucent to opaque green ...
Iron-rich sedimentary rocks have economic uses as iron ores. Iron deposits have been located on all major continents with the exception of Antarctica. They are a major source of iron and are mined for commercial use. [1] The main iron ores are from the oxide group consisting of hematite, goethite, and magnetite.
Limonite (/ ˈlaɪməˌnaɪt /) is an iron ore consisting of a mixture of hydrated iron (III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO (OH)·nH2O, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely. Limonite is one of the three principal iron ores, the ...
The modern chrysolite is a green oblong hexagonal prism of unequal sides terminated by two triangular pyramids. Topaz, or ancient chrysolite, is an octangular prism of an orange-yellow colour; it is composed of alumina, silica, hydrofluoric acid, and iron. it is found in Ceylon, Arabia, and Egypt.
Hematite, a mineral composed of ferric oxide (Fe 2 O 3), has been found on the Moon. This mineral is a product of a reaction between iron, oxygen, and liquid water. Oxygen from the Earth's atmosphere may cause this reaction as indicated by there being more hematite on the side of the Moon facing the Earth. [45]
Maghemite (Fe 2 O 3, γ-Fe 2 O 3) is a member of the family of iron oxides. It has the same formula as hematite, but the same spinel ferrite structure as magnetite (Fe3O4) and is also ferrimagnetic. It is sometimes spelled as "maghaemite". Maghemite can be considered as an Fe (II)-deficient magnetite with formula [6] where represents a vacancy ...