chemia-kuchni: Nickel

Evidence: 100 • authority: 72

Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slow to react with air under standard conditions because a passivation layer of nickel oxide that prevents further corrosion forms on the surface. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those ele…

Evidence: 50 • authority: 88

The occurrence of native nickel-iron in the serpentine rock of the eastern townships of Quebec province. Native nickel-iron has been found over a wide area in the serpentinized asbestos-bearing rock of the Eastern Townships of Quebec. The chemical composition (average of two analyses) is nickel 71.0%, iron 25.3%, cobalt 3.5%, and copper 0.2%. The nickel-iron forms a single-phase alloy with a face-centred cubic structure and a cell constant which varies from 3.551 to 3.555 A. It occurs chiefly as tiny spheroidal grains, most of which are less than 10 microns in diameter, but also as larger crenulated grains up to 100 microns in diameter, and as acicular crystals up to 100 microns in length.…

Evidence: 39 • authority: 92

The First Samples from Almahata Sitta Showing Contacts Between Ureilitic and Chondritic Lithologies: Implications for the Structure and Composition of Asteroid 2008 TC<sub>3</sub>.. Almahata Sitta (AhS), an anomalous polymict ureilite, is the first meteorite observed to originate from a spectrally classified asteroid (2008 TC 3 ). However, correlating properties of the meteorite with those of the asteroid is not straightforward because the AhS stones are diverse types. Of those studied prior to this work, 70-80% are ureilites (achondrites) and 20-30% are various types of chondrites. Asteroid 2008 TC 3 was a heterogeneous breccia that disintegrated in the atmosphere, with its cla…

Evidence: 39 • authority: 72

The geochemistry of carbon is the study of the transformations involving the element carbon within the systems of the Earth. To a large extent this study is organic geochemistry, but it also includes the very important carbon dioxide. Carbon is transformed by life, and moves between the major phases of the Earth, including the water bodies, atmosphere, and the rocky parts. Carbon is important in the formation of organic mineral deposits, such as coal, petroleum or natural gas. Most carbon is cycled through the atmosphere into living organisms and then respirated back into the atmosphere. However an important part of the carbon cycle involves the trapping of living matter into sediments. The…

Evidence: 39 • authority: 88

Formation of nickel–iron meteorites by chemical fluid transport. ABSTRACT The deposition of solid material from the gas phase via chemical vapor transport (CVT) is a well-known process of industrial and geochemical relevance. There is strong evidence that this type of thermodynamically driven chemical transport reaction plays a significant role in certain natural processes. This article presents detailed evidence that CVT is a highly plausible mechanism for the formation of iron meteorites. In this study, naturally occurring CVT is referred to as “chemical fluid transport” (CFT) and the end products deposited from the gas phase as “fluidites.” Treating iron meteorites as cosmic fluidites en…

Evidence: 34 • authority: 80

Mineralogy of Serpentinized Ultramafic Rocks and Associated Nickel Deposits

Evidence: — • authority: 72

A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star; astronomers call the brightest examples "bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater. Meteorites that are recovered after being observed as they transit the atmosphere and imp…

Evidence: — • authority: 72

Peridotite (US: PERR-ih-doh-tyte, pə-RID-ə-) is a dense, phaneritic (coarse-grained) igneous rock consisting mostly of the silicate minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica. It is high in magnesium (Mg2+), reflecting the high proportions of magnesium-rich olivine, with appreciable iron. Peridotite is derived from Earth's mantle, either as solid blocks and fragments, or as crystals accumulated from magmas that formed in the mantle. The compositions of peridotites from these layered igneous complexes vary widely, reflecting the relative proportions of pyroxenes, chromite, plagioclase, and amphibole. Peridotite is the dominant rock of t…

Evidence: — • authority: 72

Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are usually composed of greater than 90% mafic minerals (dark colored, high magnesium and iron content). Earth's mantle is composed of ultramafic rocks. Ultrabasic is a more inclusive term that includes igneous rocks with low silica content that may not be extremely enriched in Fe and Mg, such as carbonatites and ultrapotassic igneous rocks.

Evidence: — • authority: 80

High temperature resistance studies of thin nickel foils exposed to hydrogen and oxygen

Evidence: — • authority: 80

Reflectivity changes of optically-thin nickel films exposed to oxygen

Evidence: — • authority: 80

Rare earth elements in rock-forming minerals from ultramafic and mafic rocks