Physics

Nickel

Nickel Definition Nickel is a silvery, hard, ductile metallic element that occurs in ores along with iron or magnesium. It occurs sparingly in nature in minerals such as pentlandite and niccolite. It is present in most meteorites. It resists oxidation and corrosion and is used to make alloys such.....

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Chromite

Chromite Definition Chromite is a brownish-black mineral consisting of a ferrous chromic oxide in cubic crystalline form, occurring principally in basic igneous rocks: the only commercial source of chromium and its compounds. It is an oxide mineral composed of chromium, iron and oxygen (FeCr2O4)......

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Lava Tube

Lava Tube Definition Lava tubes are the longest and most complicated of volcanic caves. They are the channels of rivers of lava that at some earlier time flowed downslope from a volcanic vent or fissure. The size of these tubes is very variable. Thus, the Kazumura, in Hawaii, at 59.3 km, is the l.....

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Volcanic Rock

Volcanic Rock Definition Volcanic rock is an igneous rock of volcanic origin. It differs from other igneous rock by being of volcanic origin. Volcanic rocks are usually fine-grained or aphanitic to glassy in texture. They often contain clasts of other rocks and phenocrysts. Volcanic rocks are amo.....

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Komatiite

Komatiite Definition Komatiite is relatively common in Archean greenstone belts, rare in Proterozoic belts, and virtually absent in younger regions. The type area is the 3.5 Ga Barberton greenstone belt of South Africa where the rock type was first discovered. True komatiites are very rare and es.....

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Putnisite

Putnisite Definition The mineral, named putnisite, appears purple and translucent, and contains strontium, calcium, chromium, sulphur, carbon, oxygen and hydrogen, a very unusual combination. It was discovered on the Polar Bear Peninsula in Shire of Dundas, Western Australia in 2007 during mining.....

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Tourmaline

Tourmaline Definition Tourmaline is Any of several minerals having the general chemical formula (Na,Ca)(Mg,Fe,Al,Li)3 Al6 (BO3)3 Si6 O18 (OH)4 . Tourmaline occurs in many different translucent colors, usually in crystals shaped like 3-, 6-, or 9-sided prisms. It occurs in igneous and metamorphic .....

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Spodumene

Spodumene Definition Spodumene is a greyish-white, green, or lilac pyroxene mineral consisting of lithium aluminium silicate in monoclinic crystalline form. It’s formula: LiAlSi 2O6. It is a lithium aluminum silicate mineral usually found in pegmatite veins. It is an important ore of lithium an.....

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Hypersthene

Hypersthene Definition Hypersthene is a green, brown, or black pyroxene mineral consisting of magnesium iron silicate in orthorhombic crystalline form. It is a common rock-forming inosilicate mineral belonging to the group of orthorhombic pyroxenes. Many references have formally abandoned this te.....

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Beryl

Beryl Definition Beryl is a usually green or bluish-green hexagonal mineral occurring as transparent to translucent prisms in igneous and metamorphic rocks. Transparent varieties, such as emeralds and aquamarine, are valued as gems. Beryl is the main source of the element beryllium. Its chemical .....

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Amethyst

Amethyst Definition Amethyst is a purple or violet, transparent form of quartz used as a gemstone. The color is caused by the presence of iron compounds in the crystal structure. It is the most popular purple gem and one of the most popular gemstones of all time. Amethyst is used to produce facet.....

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Amphibole

Amphibole Definition Amphibole is any of a large group of usually dark minerals composed of a silicate joined to various metals, such as magnesium, iron, calcium or sodium. Amphiboles can be green, black, colorless, white, yellow, blue, or brown. The International Mineralogical Association curren.....

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