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Grossular
Grossular is a calcium-aluminium species of the garnet group of minerals. It has the chemical formula of Ca3Al2(SiO4)3 but the calcium may, in part, be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, ''grossularia'', in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Grossular is a gemstone. In geological literature, grossular has often been called ''grossularite''. Since 1971, however, use of the term grossularite for the mineral has been discouraged by the International Mineralogical Association. Hessonite Hessonite or "cinnamon stone" is a common variety of grossular with the general formula: Ca3Al2Si3O12. The name comes from the (hēssōn), meaning ''inferior''; an allusion to its lower hardness and lower density than most other garnet species varieties. It has a characteristic red ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hessonite
Grossular is a calcium-aluminium species of the garnet group of minerals. It has the chemical formula of Ca3Al2(SiO4)3 but the calcium may, in part, be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, ''grossularia'', in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Grossular is a gemstone. In geological literature, grossular has often been called ''grossularite''. Since 1971, however, use of the term grossularite for the mineral has been discouraged by the International Mineralogical Association. Hessonite Hessonite or "cinnamon stone" is a common variety of grossular with the general formula: Ca3Al2Si3O12. The name comes from the (hēssōn), meaning ''inferior''; an allusion to its lower hardness and lower density than most other garnet species varieties. It has a characteristic red col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garnet
Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnet minerals, while sharing similar physical and crystallographic properties, exhibit a wide range of chemical compositions, defining distinct species. These species fall into two primary solid solution series: the pyralspite series (pyrope, almandine, spessartine), with the general formula [Mg,Fe,Mn]3Al2(SiO4)3; and the ugrandite series (uvarovite, grossular, andradite), with the general formula Ca3[Cr,Al,Fe]2(SiO4)3. Notable varieties of grossular include Grossular#Hessonite, hessonite and tsavorite. Etymology The word ''garnet'' comes from the 14th-century Middle English word ''gernet'', meaning 'dark red'. It is borrowed from Old French ''grenate'' from Latin language, Latin ''granatus,'' from ''granum'' ('grain, seed'). This is possibly a reference to ''mela granatum'' or even ''pomum granatum'' ('pomegranate', ''Punica granatum''), a plant whose fruits conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nesosilicate
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, the crystalline forms of silica (silicon dioxide, ) are usually considered to be tectosilicates, and they are classified as such in the Dana system (75.1). However, the Nickel-Strunz system classifies them as oxide minerals (4.DA). Silica is found in nature as the mineral quartz, and its polymorphs. On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. Living organisms also contribute to this geologic cycle. For example, a type of plankton known as diatoms construct their exoskeletons ("frustules") from silica extracted from seaw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance 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 Geology, geological definition of mineral normally excludes compounds that occur only in living organisms. However, some minerals are often biogenic (such as calcite) or 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 (geology), 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 (geology), aggregate of two or more different types of minerals, spaci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gooseberry
Gooseberry ( or (American and northern British) or (southern British)) is a common name for many species of ''Ribes'' (which also includes Ribes, currants), as well as a large number of plants of similar appearance, and also several unrelated plants (see List of gooseberries). The berries of those in the genus ''Ribes'' (sometimes placed in the genus ''Grossularia'') are edible and may be green, orange, red, purple, yellow, white, or black. Etymology The ''goose'' in ''gooseberry'' has been mistakenly seen as a corruption of either the Dutch language, Dutch word or the allied German language, German , or of the earlier forms of the French language, French . Alternatively, the word has been connected to the Middle High German ('curl, crisped'), in Latin as . However, the ''Oxford English Dictionary'' takes the more literal derivation from ''goose'' and ''berry'' as probable because "the grounds on which plants and fruits have received names associating them with animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tsavorite
Tsavorite or tsavolite is a variety of the garnet group species grossular, a calcium-aluminium garnet with the formula Ca3 Al2 Si3 O12. Trace amounts of vanadium or chromium provide the green color. In 1967, British gem prospector and geologist Campbell R. Bridges discovered a deposit of green grossular in the mountains of Simanjiro District of Manyara Region of north-east Tanzania in a place called Lemshuko, away from Komolo, the first village. The specimens he found were of very intense color and of high transparency. The find interested the gem trade, and attempts were made to export the stones, but the Tanzanian government did not provide permits. Believing that the deposit was a part of a larger geological structure extending possibly into Kenya, Bridges began prospecting in that nation. He was successful a second time in 1971, when he found the mineral variety there, and was granted a permit to mine the deposit. The gemstone was known only to mineral specialists unti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zircon
Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of the range of substitution in zircon is (Zr1–y, REEy)(SiO4)1–x(OH)4x–y. Zircon precipitates from silicate melts and has relatively high concentrations of high field strength incompatible elements. For example, hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal system. The natural color of zircon varies between colorless, yellow-golden, red, brown, blue, and green. The name derives from the Persian ''zargun'', meaning "gold-hued". This word is changed into " jargoon", a term applied to light-colored zircons. The English word "zircon" is derived from ''Zirkon'', which is the German adaptation of this word. Yellow, orange, and red zircon is also known as " hyacint ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur Herbert Church
Sir Arthur Herbert Church (2 June 1834 – 31 May 1915) was a British chemist, expert on pottery, stones and chemistry of paintings, who discovered turacin in 1869 and several minerals, including the only British cerium mineral. He was also a talented artist and worked as a professor of chemistry at the Agricultural College in Cirencester and then at the Royal Academy of Arts. He wrote extensively on aspects of chemistry in agriculture, art, and daily life. He wrote a widely used book on paints, "The Chemistry of Paints and Painting". Early life Church was born in London, the son of John Thomas Church, a solicitor. His studied at King's College London where he showed an interest in both science and art. He spent four years from 1851 to 1855 at the Royal College of Chemistry where he, under A. W. Hofmann, studied alongside William Henry Perkin with whom he published his first research paper. The next four years were spent at Lincoln College, Oxford, where he received a BA in 1859 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship between given quantities. The plural of ''formula'' can be either ''formulas'' (from the most common English plural noun form) or, under the influence of scientific Latin, ''formulae'' (from the original Latin). In mathematics In mathematics, a formula generally refers to an equation or inequality relating one mathematical expression to another, with the most important ones being mathematical theorems. For example, determining the volume of a sphere requires a significant amount of integral calculus or its geometrical analogue, the method of exhaustion. However, having done this once in terms of some parameter (the radius for example), mathematicians have produced a formula to describe the volume of a sphere in terms of its radius: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engraved Gem
An engraved gem, frequently referred to as an intaglio, is a small and usually semi-precious gemstone that has been carved, in the Western tradition normally with images or inscriptions only on one face. The engraving of gemstones was a major luxury art form in the Ancient history, ancient world, and an important one in some later periods. Strictly speaking, ''engraving'' means carving ''in intaglio'' (with the design cut ''into'' the flat background of the stone), but relief carvings (with the design projecting ''out of'' the background as in nearly all cameo (carving), cameos) are also covered by the term. This article uses ''cameo'' in its strict sense, to denote a carving exploiting layers of differently coloured stone. The activity is also called ''gem carving'' and the artists ''gem-cutters''. References to antique gems and intaglios in a jewellery context will almost always mean carved gems; when referring to monumental sculpture, the term counter-relief, meaning the same a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Mineralogical Association
Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. The IMA is affiliated with the International Union of Geological Sciences (IUGS). The Association supports the activities of Commissions and Working Groups involved on certain aspects of mineralogical practice and facilitates interactions among mineralogists by sponsoring and organising meetings. In particular, the IMA holds its general meeting every four years. The last meeting was scheduled in 2022 in Lyon, France. Presidents The presidents of the IMA have been: * since 2024: Eiji Ohtani ** Tohoku University * 2022–2024: Hans-Peter Schertl ** Bochum University * 2020–2022: Anhuai Lu ** Peking University *2018–2020: Patrick Cordier ** Université de Lille *2016–2018: Peter C. Burns ** University of Notre Dame *2014–2016 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
