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Allanite
Allanite (also called orthite) is a sorosilicate group of minerals within the broader epidote group that contain a significant amount of rare-earth elements. The mineral occurs mainly in metamorphosed clay-rich sediments and felsic igneous rocks. It has the general formula A2M3Si3O12 H where the A sites can contain large cations such as Ca2+, Sr2+, and rare-earth elements, and the M sites admit Al3+, Fe3+, Mn3+, Fe2+, or Mg2+ among others. However, a large amount of additional elements, including Th, U, Be, Zr, P, Ba, Cr and others may be present in the mineral. The International Mineralogical Association lists four minerals in the allanite group, each recognized as a unique mineral: allanite-(Ce), allanite-(La), allanite-(Nd), and allanite-(Y), depending on the dominant rare earth present: cerium, lanthanum, neodymium or yttrium. Allanite contains up to 20% rare-earth elements and is a valuable source of them. The inclusion of thorium and other radioactive elements in allanit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidote
Epidote is a calcium aluminium iron sorosilicate mineral. Description Well developed crystals of epidote, Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH), crystallizing in the monoclinic system, are of frequent occurrence: they are commonly prismatic in habit, the direction of elongation being perpendicular to the single plane of symmetry. The name Epidote is derived from the Greek word 'epidosis', meaning "increase", in allusion to the crystal characteristic of one longer side at the base of the prism. The faces are often deeply striated and crystals are often twinned. Many of the characters of the mineral vary with the amount of iron present for instance, the color, the optical constants, and the specific gravity. The color is green, grey, brown or nearly black, but usually a characteristic shade of yellowish-green or pistachio-green. It displays strong pleochroism, the pleochroic colors being usually green, yellow and brown. Clinozoisite is green, white or pale rose-red group species c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sorosilicates
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 seawat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrognomic
Pyrognomic materials are said to become visibly incandescent at relatively low temperatures. In practice, virtually all solid or liquid substances start to visibly incandesce around 798 K (525 °C; 977 °F), with a mildly dull red color, whether or not a chemical reaction takes place that produces light as a result of an exothermic process. This limit is called the Draper point. The incandescence does not vanish below that temperature, but it is too weak in the visible spectrum to be perceivable. Pyrognomic materials are thought to visibly incandesce at much lower temperatures than the Draper point but a material with this property has never been proven to exist. Allanite and gadolinite are examples of minerals which have been claimed to exhibit true pyrognomic properties but have since been shown to exhibit thermoluminescence. The term was originally introduced by the German chemist and mineralogist Theodor Scheerer (1813-1873) in 1840, but the phenomenon had been previo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorium
Thorium is a chemical element; it has symbol Th and atomic number 90. Thorium is a weakly radioactive light silver metal which tarnishes olive grey when it is exposed to air, forming thorium dioxide; it is moderately soft, malleable, and has a high melting point. Thorium is an electropositive actinide whose chemistry is dominated by the +4 oxidation state; it is quite reactive and can ignite in air when finely divided. All known thorium isotopes are unstable. The most stable isotope, 232Th, has a half-life of 14.05 billion years, or about the age of the universe; it decays very slowly via alpha decay, starting a decay chain named the thorium series that ends at stable 208 Pb. On Earth, thorium and uranium are the only elements with no stable or nearly-stable isotopes that still occur naturally in large quantities as primordial elements. Thorium is estimated to be over three times as abundant as uranium in the Earth's crust, and is chiefly refined from monazite sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Minerals
This is a list of minerals which have Wikipedia articles. Minerals are distinguished by various chemical and physical properties. Differences in chemical composition and crystal structure distinguish the various ''species''. Within a mineral species there may be variation in physical properties or minor amounts of impurities that are recognized by mineralogists or wider society as a mineral ''variety''. Mineral variety names are listed after the valid minerals for each letter. For a more complete listing of all mineral names, see List of minerals recognized by the International Mineralogical Association. A :Varieties that are not valid species: *Adamantine spar (variety of corundum) *Agate (variety of chalcedony and quartz) *Alabaster (variety of gypsum) *Alexandrite (variety of chrysoberyl) *Allingite (synonym of amber) *Alum *Amazonite (variety of microcline) *Amethyst (purple variety of quartz) *Ametrine (variety of quartz) *Ammolite (organic; also a gemstone) *Amos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicate Minerals
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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleochroic Halo
A pleochroic halo, or radiohalo, is a microscopic, spherical shell of discolouration (pleochroism) within minerals such as biotite that occurs in granite and other igneous rocks. The halo is a zone of radiation damage caused by the inclusion of minute radioactive crystals within the host crystal structure. The inclusions are typically zircon, apatite, or titanite which can accommodate uranium or thorium within their crystal structures. One explanation is that the discolouration is caused by alpha particles emitted by the nuclei; the radius of the concentric shells are proportional to the particles' energy. Production Uranium-238 follows a sequence of decay through thorium, radium, radon, polonium, and lead. These are the alpha-emitting isotopes in the sequence. (Because of their continuous energy distribution and greater range, beta particles cannot form distinct rings.) The final characteristics of a pleochroic halo depends upon the initial isotope, and the size of each rin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Ludwig Giesecke
Carl Ludwig Giesecke FRSE (6 April 1761 in Augsburg – 5 March 1833 in Dublin) was a German actor, librettist, polar explorer and mineralogist. In his youth he was called Johann Georg Metzler; in his later career in Ireland he was Sir Charles Lewis Giesecke. Late in his life he claimed to friends to have been, in his youth, the librettist of Mozart’s famous opera The Magic Flute. Early life His father was Johann Georg Metzler, a Protestant who worked as a tailor in Augsburg. His mother was named Sibylla Magdalena Götz.Whittaker (2007, 149) He attended the Gymnasium in Augsburg,Honolka and Pauly (1990, 142) and did well academically, as is known from the surviving remarks of his schoolmaster recommending him for university study. He attended the University of Göttingen from 1781 to 1784, studying law. He also developed a side interest in mineralogy, attending the lectures of the naturalist Johann Friedrich Blumenbach. It was in 1781 that he took the pseudonym by which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland
Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenland are full Danish nationality law, citizens of Denmark and European Union citizenship, of the European Union. Greenland is one of the Special territories of members of the European Economic Area#Overseas countries and territories, Overseas Countries and Territories of the European Union and is part of the Council of Europe. It is the List of islands by area, world's largest island, and lies between the Arctic Ocean, Arctic and Atlantic oceans, east of the Arctic Archipelago, Canadian Arctic Archipelago. It is the location of the northernmost point of land in the world; Kaffeklubben Island off the northern coast is the world's Northernmost point of land, northernmost undisputed point of land—Cape Morris Jesup on the mainland was thought to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluk Island
Aluk Island or Aluk Avalleq is an island off Prins Christian Sound, in Kujalleq municipality in southern Greenland. It is located to the east of Aluk Tunorleq island. This island is the type locality for allanite a member of the epidote mineral group. See also *List of islands of Greenland The following is an alphabetical list of the islands of Greenland. Many of these islands have both a Kalaallisut language name and a Indo-European languages, European language name. Islands and archipelagoes *Aaluik *Aasiaat *Achton Friis Is ... References Islands of Greenland Kujalleq {{Greenland-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Allan (mineralogist)
Thomas Allan of Lauriston FRS FRSE FSA FLS (17 July 1777 – 12 September 1833) was a British mineralogist. Life Allan was born in Edinburgh, Scotland, on 17 July 1777, the son of Robert Allan (1748–1818), a banker. He was educated at the High School of Edinburgh and took up banking as profession, but he is remembered today for his contributions to mineral science. At an early age, Allan became fascinated with minerals, and he began to accumulate a large mineral collection that was subsequently bequeathed to his son Robert Allan FRSE. This collection was later incorporated into Robert Greg's, which was ultimately acquired by the British Museum of Natural History in the mid-19th century. In 1813, Allan was influential in securing a mineralogy post in the Dublin Philosophical Society for German mineralogist Karl Ludwig Giesecke (1761–1833). Allan was elected as Fellow of the Royal Society of Edinburgh in 1805, his proposers being Sir James Hall, William Wright, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scottish People
Scottish people or Scots (; ) are an ethnic group and nation native to Scotland. Historically, they emerged in the Scotland in the Early Middle Ages, early Middle Ages from an amalgamation of two Celtic peoples, the Picts and Gaels, who founded the Kingdom of Scotland (or ''Kingdom of Alba, Alba'') in the 9th century. In the following two centuries, Celtic-speaking Hen Ogledd, Cumbrians of Kingdom of Strathclyde, Strathclyde and Germanic-speaking Anglo-Saxons, Angles of Northumbria became part of Scotland. In the Scotland in the High Middle Ages, High Middle Ages, during the 12th-century Davidian Revolution, small numbers of Normans, Norman nobles migrated to the Lowlands. In the 13th century, the Norse-Gaels of the Kingdom of the Isles, Western Isles became part of Scotland, followed by the Norsemen, Norse of the Northern Isles in the 15th century. In modern usage, "Scottish people" or "Scots" refers to anyone whose linguistic, cultural, family ancestral or genetic origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
