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Paramelaconite
Paramelaconite is a rare, black-colored copper(I,II) oxide mineral with formula CuCuO3 (or Cu4O3). It was discovered in the Copper Queen Mine in Bisbee, Arizona, about 1890. It was described in 1892 and more fully in 1941. Its name is derived from the Greek word for "near" and the similar mineral melaconite, now known as tenorite. Description and occurrence Paramelaconite is black to black with a slight purple tint in color, and is white with a pinkish brown tint in reflected light. The mineral occurs with massive habit or as crystals up to . A yellow color is formed when the mineral is dissolved in hydrochloric acid, a blue color when dissolved in nitric acid, and a slightly brown precipitate when exposed to ammonium hydroxide. When heated, paramelaconite breaks down into a mixture of tenorite and cuprite. Paramelaconite is a very rare mineral; many specimens purported as such are in fact mixtures of cuprite and tenorite. Paramelaconite forms as a secondary mineral in hydrot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxide Mineral
The oxide mineral class includes those minerals in which the oxide anion (O2−) is bonded to one or more metal alloys. The hydroxide-bearing minerals are typically included in the oxide class. Minerals with complex anion groups such as the silicates, sulfates, carbonates and phosphates are classed separately. Simple oxides *XO form **Periclase group *** Periclase *** Manganosite **Zincite group *** Zincite *** Bromellite *** Tenorite *** Litharge * form ** Cuprite **Ice * form **Hematite group ***Corundum ***Hematite *** Ilmenite * form **Rutile group ***Rutile *** Pyrolusite *** Cassiterite ** Baddeleyite ** Uraninite ** Thorianite * form **Spinel group ***Spinel ***Gahnite ***Magnetite *** Franklinite ***Chromite ** Chrysoberyl ** Columbite *Hydroxide subgroup: **Brucite ** Manganite ** Romanèchite **Goethite group: *** Diaspore ***Goethite Nickel–Strunz class 4: oxides IMA-CNMNC proposes a new hierarchical scheme (Mills et al., 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrothermal Synthesis
Hydrothermal synthesis includes the various techniques of synthesizing substances from high-temperature aqueous solutions at high pressures; also termed "hydrothermal method". The term "hydrothermal" is of geologic origin. Geochemists and mineralogists have studied hydrothermal phase equilibria since the beginning of the twentieth century. George W. Morey at the Carnegie Institution and later, Percy W. Bridgman at Harvard University did much of the work to lay the foundations necessary to containment of reactive media in the temperature and pressure range where most of the hydrothermal work is conducted. In the broadest definition, a process is considered hydrothermal if it involves water temperatures above and pressures above 1 atm. In the context of material science, hydrothermal synthesis focuses on the production of single crystal. Under high temperature > (300 °C) and pressure (> 100 atm), ordinarily insoluble minerals become soluble in water. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Ammonia
Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests a Salt (chemistry), salt with the chemical formula, composition , it is impossible to isolate samples of NH4OH. The ions and OH− do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions. The concentration of such solutions is measured in units of the Baumé scale (density), with 26 degrees Baumé (about 30% of ammonia by weight at ) being the typical high-concentration commercial product. Basicity of ammonia in water In aqueous solution, ammonia deprotonation, deprotonates a small fraction of the water to give ammonium and hydroxide according to the following chemical equilibrium, equilibrium: : NH3 + H2O ⇌ + OH−. In a 1 Molar concentra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Bureau Of Standards
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical science laboratory programs that include nanoscale science and technology, engineering, information technology, neutron research, material measurement, and physical measurement. From 1901 to 1988, the agency was named the National Bureau of Standards. History Background The Articles of Confederation, ratified by the colonies in 1781, provided: The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States. Article 1, section 8, of the Constitution of the United States, ratified in 1789, granted these powers to the new Con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Microscope
An electron microscope is a microscope that uses a beam of electrons as a source of illumination. It uses electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing it to produce magnified images or electron diffraction patterns. As the wavelength of an electron can be up to 100,000 times smaller than that of visible light, electron microscopes have a much higher Angular resolution, resolution of about 0.1 nm, which compares to about 200 nm for optical microscope, light microscopes. ''Electron microscope'' may refer to: * Transmission electron microscopy, Transmission electron microscope (TEM) where swift electrons go through a thin sample * Scanning transmission electron microscopy, Scanning transmission electron microscope (STEM) which is similar to TEM with a scanned electron probe * Scanning electron microscope (SEM) which is similar to STEM, but with thick samples * Electron microprobe sim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Structure
In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter. The smallest group of particles in a material that constitutes this repeating pattern is the unit cell of the structure. The unit cell completely reflects the symmetry and structure of the entire crystal, which is built up by repetitive translation of the unit cell along its principal axes. The translation vectors define the nodes of the Bravais lattice. The lengths of principal axes/edges, of the unit cell and angles between them are lattice constants, also called ''lattice parameters'' or ''cell parameters''. The symmetry properties of a crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Group
In mathematics, physics and chemistry, a space group is the symmetry group of a repeating pattern in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of the pattern that leave it unchanged. In three dimensions, space groups are classified into 219 distinct types, or 230 types if chiral copies are considered distinct. Space groups are discrete cocompact groups of isometries of an oriented Euclidean space in any number of dimensions. In dimensions other than 3, they are sometimes called Bieberbach groups. In crystallography, space groups are also called the crystallographic or Fedorov groups, and represent a description of the symmetry of the crystal. A definitive source regarding 3-dimensional space groups is the ''International Tables for Crystallography'' . History Space groups in 2 dimensions are the 17 wallpaper groups which have been known for several centuries, though the proof that the list ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetragonal Crystal System
In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square base (''a'' by ''a'') and height (''c'', which is different from ''a''). Bravais lattices There are two tetragonal Bravais lattices: the primitive tetragonal and the body-centered tetragonal. The body-centered tetragonal lattice is equivalent to the primitive tetragonal lattice with a smaller unit cell, while the face-centered tetragonal lattice is equivalent to the body-centered tetragonal lattice with a smaller unit cell. Crystal classes The point groups that fall under this crystal system are listed below, followed by their representations in international notation, Schoenflies notation, orbifold notation, Coxeter notation and mineral examples.Hurlbut, Cornelius S.; Klein, Cornelis, 1985, ''Manual of Mineralogy'', 20th ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plancheite
Plancheite is a hydrated copper silicate mineral with the formula Cu8 Si8 O22( OH)4•( H2O). It is closely related to shattuckite in structure and appearance, and the two minerals are often confused. Structure Plancheite is a chain silicate (inosilicate), with double chains of silica tetrahedra parallel to the c crystal axis. It occurs as sprays of acicular or fibrous radial clusters, with fibers extended parallel to the chains, i.e. along the c crystal axis; it can also form tiny tabular or platy crystals. It is a member of the orthorhombic crystal class m m m (2/m 2/m 2/m), which is the most symmetrical class in the orthorhombic system. Properties Usually a pale turquoise-blue, with a pale blue streak and an adamantine to silky luster. It is quite hard, with hardness 5.5 to 6, close to that of feldspar, and specific gravity 3.6 to 3.8. Optically it is biaxial (+), with refractive indices between 1.64 and 1.74, and pleochroic. Environment Plancheite is a secondary mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malachite
Malachite () is a copper Carbonate mineral, carbonate hydroxide mineral, with the chemical formula, formula Basic copper carbonate, Cu2CO3(OH)2. This opaque, green-banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmite, stalagmitic masses, in fractures and deep, underground spaces, where the water table and hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare, but occur as slender to Acicular (crystal habit), acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur. Etymology and history The stone's name derives (via , , and Middle English ''melochites'') from Greek language, Greek Μολοχίτης λίθος ''molochites lithos'', "mallow-green stone", from μολόχη ''molochē'', variant of μαλάχη ''malāchē'', "mallow". The mineral was given this name due to its resemblance to the leaves of the Malva, mallow plant. Copper (Cu2+) g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Goethite
Goethite (, ) is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the α- polymorph. It is found in soil and other low-temperature environments such as sediment. Goethite has been well known since ancient times for its use as a pigment (brown ochre). Evidence has been found of its use in paint pigment samples taken from the caves of Lascaux in France. It was first described in 1806 based on samples found in the Hollertszug Mine in Herdorf, Germany. The mineral was named after the German polymath and poet Johann Wolfgang von Goethe (1749–1832). Composition Goethite is an iron oxyhydroxide containing ferric iron. It is the main component of rust and bog iron ore. Goethite's hardness ranges from 5.0 to 5.5 on the Mohs Scale, and its specific gravity varies from 3.3 to 4.3. The mineral forms prismatic needle-like crystals ("needle ironstone") but is more typically massive. Feroxyhyte and lepidocrocite are both polymorphs of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
