HOME
*



picture info

Pacitan (town)
Pacitan Regency ( id, Kabupaten Pacitan) is a regency located in the southwestern corner of East Java Province, with Central Java Province on its western border. Located between 7.55° - 8.17°S and 110.55° - 111.25°E. The borders of Pacitan Regency are: Wonogiri Regency (Central Java) in the west, Ponorogo Regency and Trenggalek Regency in the east, and the Indian Ocean in the south. It covers an area of 1,389.87 km2 and had a population of 540,881 at the 2010 census and 586,110 at the 2020 census. The capital of Pacitan Regency is Pacitan town. The majority of citizens in Pacitan speak Javanese as their first language, while speaking Indonesian as a second language. Geography The area of Pacitan Regency is about 1,389.87 km2. Most of it is mountainous and rocky, also having a few rocky canyons. That sort of geography covers about 88% of the regency, and this is because Pacitan is located in the Thousand Mountains. The highest mountain in Pacitan is Mount Lima in ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

List Of Regencies And Cities Of Indonesia
Regencies (''kabupaten'') and cities (''kota'') are the second-level administrative subdivision in Indonesia, immediately below the provinces, and above the districts. Regencies are roughly equivalent to American counties, although most cities in the United States are below the counties. Following the implementation of decentralization beginning on 1 January 2001, regencies and city municipalities became the key administrative units responsible for providing most governmental services. Each of regencies and cities has their own local government and legislative body. The difference between a regency and a city lies in demography, size, and economy. Generally, a regency comprises a rural area larger than a city, but also often includes various towns. A city usually has non-agricultural economic activities. A regency is headed by a regent (''bupati''), while a city is headed by a mayor (''wali kota''). All regents, mayors, and members of legislatures are directly elected via ele ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Dolomite (mineral)
Dolomite () is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite. An alternative name sometimes used for the dolomitic rock type is dolostone. History As stated by Nicolas-Théodore de Saussure the mineral dolomite was probably first described by Carl Linnaeus in 1768. In 1791, it was described as a rock by the French naturalist and geologist Déodat Gratet de Dolomieu (1750–1801), first in buildings of the old city of Rome, and later as samples collected in the mountains now known as the Dolomite Alps of northern Italy. Nicolas-Théodore de Saussure first named the mineral (after Dolomieu) in March 1792. Properties The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, tan, gray, or pink crystals. Dolomite is a double carbonate, having an alternating structural arrangement of calcium and magnesium ions. Unless it ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous ( Pennsylvanian) and Permian times. Many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution. With the invention of the steam engine, coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over a third of its electricity. Some iron ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. Quartz is the mineral defining the val ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Phosphate Rock
Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P2O5). Marketed phosphate rock is enriched ("beneficiated") to at least 28%, often more than 30% P2O5. This occurs through washing, screening, de-liming, magnetic separation or flotation. By comparison, the average phosphorus content of sedimentary rocks is less than 0.2%.Blatt, Harvey and Robert J. Tracy, ''Petrology'', Freeman, 1996, 2nd ed. pp. 345–349 The phosphate is present as fluorapatite Ca5(PO4)3F typically in cryptocrystalline masses (grain sizes < 1 μm) referred to as -sedimentary apatite deposits of uncertain origin. It is also present as
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. Alabaster, a fine-grained white or lightly tinted variety of gypsum, has been used for sculpture by many cultures including Ancient Egypt, Mesopotamia, Ancient Rome, the Byzantine Empire, and the Nottingham alabasters of Medieval England. Gypsum also crystallizes as translucent crystals of selenite. It forms as an evaporite mineral and as a hydration product of anhydrite. The Mohs scale of mineral hardness defines gypsum as hardness value 2 based on scratch hardness comparison. Etymology and history The word ''gypsum'' is derived from the Greek word (), "plaster". Because the quarries of the Montmartre district of Paris have long furnished burnt gypsum (calcined gypsum) used for various purposes, this dehydrated gypsum became known ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on Scratch hardness, scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German ''Calcit'', a term from the 19th century that came from the Latin word for Lime (material), lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeology, archaeologists and stone trade pr ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Pyrophyllite
Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O10(OH)2. It occurs in two forms (habits): crystalline folia and compact masses; distinct crystals are not known. The folia have a pronounced pearly luster, owing to the presence of a perfect cleavage parallel to their surfaces: they are flexible but not elastic, and are usually arranged radially in fan-like or spherical groups. This variety, when heated , exfoliates and swells up to many times its original volume, hence the name pyrophyllite, from the Greek ''pyro-'' (πυρο-, the combining form of πῦρ fire) and ''phyllos'' (a leaf), given by R. Hermann in 1829. The color of both varieties is white, pale green, greyish or yellowish; they are very soft (hardness of 1.0 to 1.5) and are greasy to the touch. The specific gravity is 2.65 - 2.85. The two varieties are thus very similar to talc. Occurrence Pyrophyllite occurs in phyllite and schistose rocks, often associated with kyanite, o ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Bentonite
Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-montmorillonite. Bentonite usually forms from the weathering of volcanic ash in seawater, or by hydrothermal circulation through the porosity of volcanic ash beds, which converts (devitrification) the volcanic glass ( obsidian, rhyolite, dacite) present in the ash into clay minerals. In the mineral alteration process, a large fraction (up to 40-50 wt.%) of amorphous silica is dissolved and leached away, leaving the bentonite deposit in place. Bentonite beds are white or pale blue or green (traces of reduced ) in fresh exposures, turning to a cream color and then yellow, red, or brown (traces of oxidized ) as the exposure is weathered further. As a swelling clay, bentonite has the ability to absorb large quantities of water, which increa ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Ball Clay
Ball clays are kaolinitic sedimentary clays that commonly consist of 20–80% kaolinite, 10–25% mica, 6–65% quartz. Localized seams in the same deposit have variations in composition, including the quantity of the major minerals, accessory minerals and carbonaceous materials such as lignite. They are fine-grained and plastic in nature, and, unlike most earthenware clays, produce a fine quality white-coloured pottery body when fired, which is the key to their popularity with potters. Ball clays are relatively scarce deposits due to the combination of geological factors needed for their formation and preservation. They are mined in parts of the Eastern United States and from three sitesThe Bovey Basin in South Devon, the Petrockstowe Basin in North Devon and the Wareham Basin in South Dorset. in Devon and Dorset in South West England. They are commonly used in the construction of many ceramic articles, where their primary role, apart from their white colour, is either to imp ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldspars and the ''alkali'' (potassium-sodium) feldspars. Feldspars make up about 60% of the Earth's crust, and 41% of the Earth's continental crust by weight. Feldspars crystalize from magma as both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. Compositions The feldspar group of minerals consists of tectosilicates, silicate minerals in which silicon ions are linked by shared oxygen ions to form a three-dimensional network. Compositions of major elements in common feldspars can be expressed in terms of three endmembers: * potassium feldspar (K-spar) ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]