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Spessartine
Spessartine is a nesosilicate, manganese aluminium garnet species, Mn2+3Al2(SiO4)3. Gemological Institute of America, ''GIA Gem Reference Guide'' 1995, This mineral is sometimes mistakenly referred to as ''spessartite''. Spessartine's name is a derivative of Spessart in Bavaria, Germany, the type locality of the mineral. It occurs most often in granite pegmatite and allied rock types and in certain low-grade metamorphic phyllites. Sources include Australia, Myanmar, India, Afghanistan, Israel, Madagascar, Namibia, Nigeria, Mozambique, Tanzania and the United States. Spessartine of an orange-yellow has been called ''Mandarin garnet'' and is found in Madagascar. Violet-red spessartines are found in rhyolites in Colorado and Maine. In Madagascar, spessartines are exploited either in their bedrock or in alluvium. The orange garnets result from sodium-rich pegmatites. Spessartines are found in bedrock in the highlands in the Sahatany valley. Those in alluvium are generally found ... [...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] |
Lamprophyre
Lamprophyres () are uncommon, small-volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks, and small intrusions. They are alkaline silica- undersaturated mafic or ultramafic rocks with high magnesium oxide, >3% potassium oxide, high sodium oxide, and high nickel and chromium. Lamprophyres occur throughout all geologic eras. Archaean examples are commonly associated with lode gold deposits. Cenozoic examples include magnesian rocks in Mexico and South America, and young ultramafic lamprophyres from Gympie in Australia with 18.5% MgO at ~250 Ma. Petrology Modern science treats lamprophyres as a catch-all term for ultrapotassic mafic igneous rocks which have primary mineralogy consisting of amphibole or biotite, and with feldspar in the groundmass. Lamprophyres are not amenable to classification according to modal proportions, such as the system QAPF, because of their peculiar mineralogy, nor compositional discrimination diagrams, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllite
Phyllite ( ) is a type of foliation (geology), foliated metamorphic rock formed from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. It is primarily composed of quartz, sericite mica, and chlorite group, chlorite. Phyllite has fine-grained mica flakes, whereas slate has extremely fine mica flakes, and schist has large mica flakes, all mica flakes of which have achieved a preferred orientation. Among foliated metamorphic rocks, it represents a gradation in the degree of metamorphism between slate and schist. The minute crystals of graphite, sericite, or chlorite, or the translucent fine-grained white mica, impart a silky, sometimes golden sheen to the surfaces of cleavage (geology), cleavage, called "phyllitic luster". The word comes from the Greek ''phyllon'', meaning "leaf". The protolith (or parent rock) for phyllite is shale or pelite; or slate, which in turn came ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Almandine
Almandine (), also known as almandite, is a mineral belonging to the garnet group. The name is a corruption of alabandicus, which is the name applied by Pliny the Elder to a stone found or worked at Alabanda, a town in Caria in Asia Minor. Almandine is an iron aluminum garnet, of deep red color, inclining to purple. It is frequently cut with a convex face, or en cabochon, and is then known as carbuncle. Viewed through the spectroscope in a strong light, it generally shows three characteristic absorption bands. Almandine is one end-member of a mineral solid solution series, with the other end member being the garnet pyrope. The almandine crystal formula is: Fe3Al2(SiO4)3. Magnesium substitutes for the iron with increasingly pyrope-rich composition. Almandine, , is the ferrous iron end member of the class of garnet minerals representing an important group of rock-forming silicates, which are the main constituents of the Earth's crust, upper mantle and transition zone. Alman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid Solution
A solid solution, a term popularly used for metals, is a homogeneous mixture of two compounds in solid state and having a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The word "solution" is used to describe the intimate mixing of components at the atomic level and distinguishes these homogeneous materials from physical mixtures of components. Two terms are mainly associated with solid solutions – ''solvents'' and ''solutes,'' depending on the relative abundance of the atomic species. In general if two compounds are isostructural then a solid solution will exist between the end members (also known as parents). For example sodium chloride and potassium chloride have the same cubic crystal structure so it is possible to make a pure compound with any ratio of sodium to potassium (Na1-xKx)Cl by dissolving that ratio of NaCl and KCl in water and then evaporating the solution. A member of this family is sold under the bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maevatanana
Maevatanana is an urban municipality in Madagascar. The city is in the central-north part of the island, at the Ikopa River, and is connected by the national road RN 4 to Antananarivo and Mahajanga. The altitude is low and as it is located far from the coast, temperatures tend to be high. The city belongs to the district of Maevatanana, which is a part of Betsiboka Region. Maevatanana is the capital of the Betsiboka region, and the population of the commune was estimated to be approximately 24,000 in 2001 commune census. In addition to primary schooling the town offers secondary education at both junior and senior levels. Maevatanana hosts the annex of the University Institute of Management and Administration (IUGM) of the University of Mahajanga. The town has a permanent court and hospital. The majority 60% of the population of the commune are farmers, while an additional 7% receive their livelihood from raising livestock. The most important crops are rice and tobacco; also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maine
Maine ( ) is a U.S. state, state in the New England region of the United States, and the northeasternmost state in the Contiguous United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Provinces and territories of Canada, Canadian provinces of New Brunswick and Quebec to the northeast and northwest, and shares a maritime border with Nova Scotia. Maine is the largest U.S. state, state in New England by total area, nearly larger than the combined area of the remaining five states. Of the List of states and territories of the United States, 50 U.S. states, it is the List of U.S. states and territories by area, 12th-smallest by area, the List of U.S. states and territories by population, 9th-least populous, the List of U.S. states by population density, 13th-least densely populated, and the most rural. Maine's List of capitals in the United States, capital is Augusta, Maine, Augusta, and List of municipalities in Maine, its most populous c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado
Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, and Oklahoma to the southeast. Colorado is noted for its landscape of mountains, forests, High Plains (United States), high plains, mesas, canyons, plateaus, rivers, and desert lands. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains. Colorado is the List of U.S. states and territories by area, eighth-largest U.S. state by area and the List of U.S. states and territories by population, 21st by population. The United States Census Bureau estimated the population of Colorado to be 5,957,493 as of July 1, 2024, a 3.2% increase from the 2020 United States census. The region has been inhabited by Native Americans in the United St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix (geology), groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite. Its high silica content makes rhyolitic magma extremely viscosity, viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been used extensively for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orange (color)
Orange is the colour between yellow and red on the spectrum of visible light. The human eyes perceive orange when observing light with a dominant wavelength between roughly 585 and 620 nanometres. In traditional colour theory, it is a secondary colour of pigments, produced by mixing yellow and red. In the RGB colour model, it is a tertiary colour. It is named after the fruit of the same name. The orange colour of many fruits and vegetables, such as carrots, pumpkins, sweet potatoes, and oranges, comes from carotenes, a type of photosynthetic pigment. These pigments convert the light energy that the plants absorb from the Sun into chemical energy for the plants' growth. Similarly, the hues of autumn leaves are from the same pigment after chlorophyll is removed. In Europe and the United States, surveys show that orange is the colour most associated with amusement, the unconventional, extroversion, warmth, fire, energy, activity, danger, taste and aroma, the autumn and Allh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanzania
Tanzania, officially the United Republic of Tanzania, is a country in East Africa within the African Great Lakes region. It is bordered by Uganda to the northwest; Kenya to the northeast; the Indian Ocean to the east; Mozambique and Malawi to the south; Zambia to the southwest; and Rwanda, Burundi, and the Democratic Republic of the Congo to the west. According to a 2024 estimate, Tanzania has a population of around 67.5 million, making it the most populous country located entirely south of the equator. Many important hominid fossils have been found in Tanzania. In the Stone and Bronze Age, prehistoric migrations into Tanzania included South Cushitic languages, Southern Cushitic speakers similar to modern day Iraqw people who moved south from present-day Ethiopia; Eastern Cushitic people who moved into Tanzania from north of Lake Turkana about 2,000 and 4,000 years ago; and the Southern Nilotic languages, Southern Nilotes, including the Datooga people, Datoog, who originated fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mozambique
Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Africa to the south and southwest. The sovereign state is separated from the Comoros, Mayotte, and Madagascar by the Mozambique Channel to the east. The capital and largest city is Maputo. Between the 7th and 11th centuries, a series of Swahili port towns developed on that area, which contributed to the development of a distinct Swahili culture and dialect. In the late medieval period, these towns were frequented by traders from Somalia, Ethiopia, Egypt, Arabia, Persia, and India. The voyage of Vasco da Gama in 1498 marked the arrival of the Portuguese Empire, Portuguese, who began a gradual process of colonisation and settlement in 1505. After over four centuries of Portuguese Mozambique, Portuguese rule, Mozambique Mozambican War of Indepen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
