Instruct: Given a question, retrieve passages that answer the question.
Query: Where is platinum most abundant?
Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for 80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and is a major precious metal commodity.
In the Earth's crust, thorium is much more abundant: with an abundance of 8.1 parts per million (ppm), it is one of the most abundant of the heavy elements, almost as abundant as lead (13 ppm) and more abundant than tin (2.1 ppm). This is because thorium is likely to form oxide minerals that do not sink into the core; it is classified as a lithophile. Common thorium compounds are also poorly soluble in water. Thus, even though the Earth contains the same abundances of the elements as the Solar System as a whole, there is more accessible thorium than heavy platinum group metals in the crust.
Osmium (from Greek ὀσμή "osme", "smell") is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with an experimentally measured (using x-ray crystallography) density of . Manufacturers use its alloys with platinum, iridium, and other platinum-group metals to make fountain pen nib tipping, electrical contacts, and in other applications that require extreme durability and hardness. The element's abundance in the Earth's crust is among the rarest.
Osmium is a chemical element with the symbol Os and atomic number 76. It is a hard, brittle, blue-gray or blue-black transition metal in the platinum family and is the densest naturally occurring element, with a density of (slightly greater than that of iridium and twice that of lead). It is found in nature as an alloy, mostly in platinum ores; its alloys with platinum, iridium, and other platinum group metals are employed in fountain pen tips, electrical contacts, and other applications where extreme durability and hardness are needed.
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). These have similar chemical properties, but palladium has the lowest melting point and is the least dense of them.
Group D
The Sun 1,447,959 -7%
Silicon is a chemical element with symbol Si and atomic number 14. It is a hard and brittle crystalline solid with a blue-grey metallic lustre; and it is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its melting and boiling points of 1414 °C and 3265 °C respectively are the second-highest among all the metalloids and nonmetals, being only surpassed by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. More than 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust (about 28% by mass) after oxygen.
Among the notable discoveries was COROT-7b, discovered in 2009 which became the first exoplanet shown to have a rock or metal-dominated composition.
Group C
Of the 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope (except for technetium, element 43 and promethium, element 61, which have no stable isotopes). Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected. Some of these elements, notably bismuth (atomic number 83), thorium (atomic number 90), and uranium (atomic number 92), have one or more isotopes with half-lives long enough to survive as remnants of the explosive stellar nucleosynthesis that produced the heavy metals before the formation of our Solar System. At over 1.9 years, over a billion times longer than the current estimated age of the universe, bismuth-209 (atomic number 83) has the longest known alpha decay half-life of any naturally occurring element, and is almost always considered on par with the 80 stable elements. The very heaviest elements (those beyond plutonium, element 94) undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized.
Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable, with half-lives varying between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99%) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.
The combination of metals was a basic technique. Essentially, there is no such thing as 24 carat gold jewelry. Massive gold is the most malleable metal. It is almost like wax. In order to have jewelry that can pass the test of time and gravity, the Etruscans had to combine their gold with other metals.
Compared to other metals, gold is malleable, ductile, rare, and it is the only solid metallic element with a yellow color. It may easily be melted, fused, and cast without the problems of oxides and gas that are problematic with other metals such as bronzes, for example. It is fairly easy to "pressure weld", wherein similarly to clay two small pieces may be pounded together to make one larger piece. Gold is classified as a noble metal—because it does not react with most elements. It usually is found in its native form, lasting indefinitely without oxidization and tarnishing.
Several elements were discovered as a consequence of lengthy analysis and decomposition of the ore Gadolinite. As the ore was progressively analysed, the residue was first given the label ceria and then lanthana and then subsequently yttria, erbia, and terbia. In order of date discovered, the list of elements includes Cerium 58, Lanthanum 57, Erbium 68, Terbium 65, Yttrium 39, Ytterbium 70, Holmium 67, Thulium 69, Scandium 21, Praseodymium 59, Neodymium 60 and Dysprosium 66. Several of these new elements were either discovered or isolated by Carl Gustaf Mosander in the 1830s and 1840s.
Lanthanum is the third-most abundant of all the lanthanides, making up 39 mg/kg of the Earth's crust, behind neodymium at 41.5 mg/kg and cerium at 66.5 mg/kg. It is almost three times as abundant as lead in the Earth's crust. Despite being among the so-called "rare earth metals", lanthanum is thus not rare at all, but it is historically so named because it is rarer than "common earths" such as lime and magnesia, and historically only a few deposits were known. Lanthanum is considered a rare earth metal because the process to mine it is difficult, time-consuming, and expensive. Lanthanum is rarely the dominant lanthanide found in the rare earth minerals, and in their chemical formulae it is usually preceded by cerium. Rare examples of La-dominant minerals are monazite-(La) and lanthanite-(La).
The La ion is similarly-sized to the early lanthanides of the cerium group (those up to samarium and europium) that immediately follow in the periodic table, and hence it tends to occur along with them in phosphate, silicate and carbonate minerals, such as monazite (MPO) and bastnäsite (MCOF), where M refers to all the rare earth metals except scandium and the radioactive promethium (mostly Ce, La, and Y). Bastnäsite is usually lacking in thorium and the heavy lanthanides, and the purification of the light lanthanides from it is less involved. The ore, after being crushed and ground, is first treated with hot concentrated sulfuric acid, evolving carbon dioxide, hydrogen fluoride, and silicon tetrafluoride: the product is then dried and leached with water, leaving the early lanthanide ions, including lanthanum, in solution.
A goldsmith might have a wide array of skills and knowledge at their disposal. Gold, being the most malleable metal of all, offers unique opportunities for the worker. In today's world a wide variety of other metals, especially platinum alloys, also may be used frequently. 24 karat is pure gold and historically, was known as fine gold.
Mercury is a chemical element with symbol Hg and atomic number 80. It is commonly known as quicksilver and was formerly named hydrargyrum ( ). A heavy, silvery d-block element, mercury is the only metallic element that is liquid at standard conditions for temperature and pressure; the only other element that is liquid under these conditions is bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature.
Mercury is one of four terrestrial planets in the Solar System, and is a rocky body like Earth. It is the smallest planet in the Solar System, with an equatorial radius of . Mercury is also smaller—albeit more massive—than the largest natural satellites in the Solar System, Ganymede and Titan. Mercury consists of approximately 70% metallic and 30% silicate material. Mercury's density is the second highest in the Solar System at 5.427 g/cm, only slightly less than Earth's density of 5.515 g/cm. If the effect of gravitational compression were to be factored out from both planets, the materials of which Mercury is made would be denser than those of Earth, with an uncompressed density of 5.3 g/cm versus Earth's 4.4 g/cm.
In fact, recent studies of zircons (in the fall of 2008) found in Australian Hadean rock hold minerals that point to the existence of plate tectonics as early as 4 billion years ago. If this holds true, the previous beliefs about the Hadean period are far from correct. That is, rather than a hot, molten surface and atmosphere full of carbon dioxide, Earth's surface would be very much like it is today. The action of plate tectonics traps vast amounts of carbon dioxide, thereby reducing greenhouse effects, and leading to a much cooler surface temperature, and the formation of solid rock, and possibly even life.
The Marange diamond fields are an area of widespread small-scale diamond production in Chiadzwa, Mutare West, Zimbabwe. 'Although estimates of the reserves contained in this area vary wildly, some have suggested that it could be home to one of the world's richest diamond deposits'. The hugely prolific fields are regarded by some experts as the world's biggest diamond (in carats, not by value) find in more than a century. Production from Marange is controversial due to ongoing legal wrangles and government crackdowns on illegal miners and allegations of forced labour. In terms of carats produced, the Marange field is the largest diamond producing project in the world, estimated to have produced 16.9 million carats in 2013, or 13% of global rough diamond supply. Marange is estimated to have produced 12.0 million carats in 2012, 8.7 million carats in 2011, and 8.2 million carats in 2010. While some diamond mines produce rough valued at over $1000 per carat, average production at Marange is estimated at under $50 per carat.
Platinum is more likely to be affected by social, environmental, political and economic issues where as gold not as much. This is because platinum has large mineral resources already identified and is not expected to be depleted for many decades (potentially up to year 2040). Furthermore, the resource is geographically restricted with the 3 by far most significant resources BIC, The great dyke (Zimbabwe) and Noril'sk-Talnakh in Russia. An important detail to note is palladium has been and is considered as the alternative to platinum. Recently (2017), the supply-demand gap has greatly decreased. Looking at political and social issues, there have been quite a few platinum mining-related strikes since before the 21st century: 1986 Impala strike, 1986 Gencor, 2004 Impala & Anglo Plats strikes, 2007 South Africa miners' strike, 2012 Marikana killings, Lonmin 2013 strike, 2014 South African platinum strike.
Platinum has six naturally occurring isotopes: Pt, Pt, Pt, Pt, Pt, and Pt. The most abundant of these is Pt, comprising 33.83% of all platinum. It is the only stable isotope with a non-zero spin; with a spin of /, Pt satellite peaks are often observed in H and P NMR spectroscopy (i.e., Pt-phosphine and Pt-alkyl complexes). Pt is the least abundant at only 0.01%. Of the naturally occurring isotopes, only Pt is unstable, though it decays with a half-life of 6.5 years, causing an activity of 15 Bq/kg of natural platinum. Pt can undergo alpha decay, but its decay has never been observed (the half-life is known to be longer than 3.2 years); therefore, it is considered stable. Platinum also has 31 synthetic isotopes ranging in atomic mass from 166 to 204, making the total number of known isotopes 39. The least stable of these is Pt, with a half-life of 300 µs, whereas the most stable is Pt with a half-life of 50 years. Most platinum isotopes decay by some combination of beta decay and alpha decay. Pt, Pt, and Pt decay primarily by electron capture. Pt and Pt are predicted to have energetically favorable double beta decay paths.
Carbon appears to be more important than moisture in defining good habitats for nematodes in the Dry Valleys of Antarctica. "Scottnema lindsayae", a microbial feeder and the most abundant and widely distributed metazoan invertebrate, often occurs as the sole metazoan species in the McMurdo Dry Valleys. It makes its living eating bacteria and yeast out in the dry, salty soils that dominate the valleys. All other invertebrate species are more abundant in moist or saturated soils where algae and moss are more abundant. Distribution of most nematode species is correlated negatively with elevation (due to temperature and precipitation) and salinity, and positively with soil moisture, soil organic matter, and nutrient availability. "Eudorylaimus" spp. is the second most abundant nematode, followed by "Plectus murrayi" who are the least abundant nematodes. "Plectus antarcticus" eats bacteria and prefers living in ephemeral streams. An average 2-pound bag of dry valley soils contains approximately 700 nematodes, while the more fertile soil found at higher latitudes on the continent may contain approximately 4,000 nematodes.
Although the prices of some platinum group metals can be much higher, gold has long been considered the most desirable of precious metals, and its value has been used as the standard for many currencies. Gold has been used as a symbol for purity, value, royalty, and particularly roles that combine these properties. Gold as a sign of wealth and prestige was ridiculed by Thomas More in his treatise "Utopia". On that imaginary island, gold is so abundant that it is used to make chains for slaves, tableware, and lavatory seats. When ambassadors from other countries arrive, dressed in ostentatious gold jewels and badges, the Utopians mistake them for menial servants, paying homage instead to the most modestly dressed of their party.