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Mineraloids
A mineraloid is a naturally occurring mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under extreme pressure. Opal is another mineraloid because of its non-crystalline nature. Pearl is considered a mineraloid because the included calcite and/or aragonite crystals are bonded by an organic material, and there is no definite proportion of the components. Examples * Allophane, solid (IMA/CNMNC valid mineral name) * Amber, non-crystalline structure, organic * Anthracite or hard coal * Bituminous coal * Chlorophaeite * Chrysocolla, solid (IMA/CNMNC valid mineral name) * Deweylite, a mixture of serpentine and talc or stevensite * Diatomite * Ebonite, vulcanized natural or synthetic rubber (organic); lacks a crystalline structure * Fulgurite, a variety o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Minerals'; p. 1. In the series ''Geology: Landforms, Minerals, and Rocks''. Rosen Publishing Group. The geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or are organic compounds in the sense of chemistry (such as mellite). Moreover, living organisms often synthesize inorganic minerals (such as hydroxylapatite) that also occur in rocks. The concept of mineral is distinct from rock, which is any bulk solid geologic material that is relatively homogeneous at a large enough scale. A rock may consist of one type of mineral, or may be an aggregate of two or more different types of minerals, spacially segregated into distinct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Mineralogist
''American Mineralogist: An International Journal of Earth and Planetary Materials'' is a peer-reviewed scientific journal covering the general fields of mineralogy, crystallography, geochemistry, and petrology. It is an official journal of the Mineralogical Society of America, publishing both subscription and open access articles. The journal is a hybrid open-access journal. The editors-in-chief are Hongwu Xu (Los Alamos National Laboratory), and Don Baker (McGill University). History The journal was established in 1916, with the first issue appearing in July of that year, under the auspices of the ''Philadelphia Mineralogical Society'', the ''New York Mineralogical Club'', and the ''Mineral Collectors' Association''. On December 30, 1919, the Mineralogical Society of America was formed and ''American Mineralogist'' became the society's journal. Abstracting and indexing The ''American Mineralogist'' is abstracted and indexed in Chemical Abstracts, the Science Citation Index, Geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignite
Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat content. When removed from the ground, it contains a very high amount of moisture which partially explains its low carbon content. Lignite is mined all around the world and is used almost exclusively as a fuel for steam-electric power generation. The combustion of lignite produces less heat for the amount of carbon dioxide and sulfur released than other ranks of coal. As a result, environmental advocates have characterized lignite as the most harmful coal to human health. Depending on the source, various toxic heavy metals, including naturally occurring radioactive materials may be present in lignite which are left over in the coal fly ash produced from its combustion, further increasing health risks. Characteristics Lignite is brow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Libyan Desert Glass
Libyan Desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of square kilometers. Geologic origin The origin of desert glass is uncertain. Meteoritic origins have long been considered possible, and recent research links the glass to impact features, such as zircon breakdown, vaporized quartz and meteoritic metals, and to an impact crater. Some geologists associate the glass with radiative melting from meteoric large aerial bursts, making it analogous to trinitite created from sand exposed to the thermal radiation of a nuclear explosion. Libyan Desert glass has been dated as having formed about 29 million years ago. Like obsidian, it was knapped and used to make tools during the Pleistocene. The glass is nearly pure silica which requires temperatures above 1,600 °C to form – hotter than any i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leonardite
Leonardite is a soft waxy, black or brown, shiny, vitreous mineraloid that is easily soluble in alkaline solutions. It is an oxidation product of lignite, associated with near-surface mining. It is a rich source of humic acid (up to 90%) and is used as a soil conditioner, as a stabilizer for ion-exchange resins in water treatment, in the remediation of polluted environments and as a drilling additive.Hoffman, G.L., Nikols, D.J., Stuhec, S., Wilson, R.A. Evaluation of Leonardite (Humalite) Open File Report 1993-18, Resources of Alberta, Alberta Geological Survey It was named after A. G. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lechatelierite
Lechatelierite is silica glass, amorphous SiO2, non-crystalline mineraloid. Structure Lechatelierite is a mineraloid as it does not have a crystal structure. Although not a true mineral, it is often classified in the quartz mineral group. Formation One common way in which lechatelierite forms naturally is by very high temperature melting of quartz sand during a lightning strike. The result is an irregular, branching, often foamy hollow tube of silica glass called a fulgurite. Not all fulgurites are lechatelierite; the original sand must be nearly pure silica. Lechatelierite also forms as the result of high pressure shock metamorphism during meteorite impact cratering and is a common component of a type of glassy ejecta called tektites. Most tektites are blobs of impure glassy material, but tektites from the Sahara Desert in Libya and Egypt, known as ''Libyan desert glass'', are composed of almost pure silica that is almost pure lechatelierite. High pressure experiments have shown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet (lignite)
Jet is a type of lignite, the lowest rank of coal, and is a gemstone. Unlike many gemstones, jet is not a mineral, but is rather a mineraloid. It is derived from wood that has changed under extreme pressure. The English noun ''jet'' derives from the French word for the same material, (modern French ), ultimately referring to the ancient town of Gagae. Jet is either black or dark brown, but may contain pyrite inclusions which are of brassy colour and metallic lustre. The adjective " jet-black", meaning as dark a black as possible, derives from this material. Origin Jet is a product of decomposition of wood from millions of years ago, commonly the wood of trees of the family Araucariaceae. Jet is found in two forms, hard and soft. Hard jet is the result of carbon compression and salt water; soft jet may be the result of carbon compression and fresh water. Despite the name they both occupy the same area of the Mohs scale with the difference being that soft jet is more likely to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fulgurite
Fulgurites (), commonly known as "fossilized lightning", are natural tubes, clumps, or masses of sintered, vitrified, and/or fused soil, sand, rock, organic debris and other sediments that sometimes form when lightning discharges into ground. When composed of silica, fulgurites are classified as a variety of the mineraloid lechatelierite. When ordinary negative polarity cloud-ground lightning discharges into a grounding substrate, greater than 100 million volts (100 MV) of potential difference may be bridged. Such current may propagate into silica-rich quartzose sand, mixed soil, clay, or other sediments, rapidly vaporizing and melting resistant materials within such a common dissipation regime. This results in the formation of generally hollow and/or vesicular, branching assemblages of glassy tubes, crusts, and clumped masses. Fulgurites have no fixed composition because their chemical composition is determined by the physical and chemical properties of whatever material is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ebonite
Ebonite is a brand name for a material generically known as hard rubber, and is obtained via vulcanizing natural rubber for prolonged periods. Ebonite may contain from 25% to 80% sulfur and linseed oil. Its name comes from its intended use as an artificial substitute for ebony wood. The material has also been called ''vulcanite'', although that name formally refers to the mineral vulcanite. Charles Goodyear's brother Nelson Goodyear experimented with the chemistry of ebonite composites. In 1851 he used zinc oxide as a filler. Hugh Silver was responsible for giving it its name. Properties The sulfur percentage and the applied temperatures and duration of vulcanizing are the main variables that determine the technical properties of the hard rubber polysulfide elastomer. The occurring reaction is basically addition of sulfur at the double bonds, forming intramolecular ring structures, so a large portion of the sulfur is highly cross-linked in the form of intramolecular addition. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatomite
Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to less than 1 mm, but typically 10 to 200 μm. Depending on the granularity, this powder can have an abrasive feel, similar to pumice powder, and has a low density as a result of its high porosity. The typical chemical composition of oven-dried diatomaceous earth is 80–90% silica, with 2–4% alumina (attributed mostly to clay minerals), and 0.5–2% iron oxide. Diatomaceous earth consists of the fossilized remains of diatoms, a type of hard-shelled microalgae. It is used as a filtration aid, mild abrasive in products including metal polishes and toothpaste, mechanical insecticide, absorbent for liquids, matting agent for coatings, reinforcing filler in plastics and rubber, anti-block in plastic films, porous support for chemic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stevensite
Stevensite is white clay mineral. The mineral is a member of smectite. The mineral is named after Edwin Augustus Stevens Edwin Augustus Stevens (July 28, 1795 – August 7, 1868) was an American engineer, inventor, and entrepreneur who left a bequest that was used to establish the Stevens Institute of Technology. Life Stevens was born at Castle Point, Hobo .... Stevensite can be found Dean Quarry. References {{Mineral-stub Smectite group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Talc
Talc, or talcum, is a Clay minerals, clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening agent and lubricant. It is an ingredient in ceramics, paints, and roofing material. It is a main ingredient in many cosmetics. It occurs as Foliation (geology), foliated to Fiber, fibrous masses, and in an exceptionally rare crystal form. It has a perfect cleavage (crystal), basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional ped, platy form. The Mohs scale of mineral hardness, based on Scratch hardness, scratch hardness comparison, defines value 1 as the hardness of talc, the softest mineral. When scraped on a streak (mineralogy), streak plate, talc produces a white streak; though this indicator is of little importance, because most silicate minerals produce a white streak. Talc is translucent to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
