The mineral pyrite, or iron pyrite known as fool's gold, is an iron sulfide with the chemical formula FeS2. Pyrite is considered the most common of the sulfide minerals. Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold; the color has led to the nicknames brass and Brazil used to refer to pyrite found in coal. The name pyrite is derived from the Greek πυρίτης, "of fire" or "in fire", in turn from πύρ, "fire". In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel. By Georgius Agricola's time, c. 1550, the term had become a generic term for all of the sulfide minerals. Pyrite is found associated with other sulfides or oxides in quartz veins, sedimentary rock, metamorphic rock, as well as in coal beds and as a replacement mineral in fossils, but has been identified in the sclerites of scaly-foot gastropods. Despite being nicknamed fool's gold, pyrite is sometimes found in association with small quantities of gold.
Gold and arsenic occur as a coupled substitution in the pyrite structure. In the Carlin–type gold deposits, arsenian pyrite contains up to 0.37% gold by weight. Pyrite enjoyed brief popularity in the 16th and 17th centuries as a source of ignition in early firearms, most notably the wheellock, where a sample of pyrite was placed against a circular file to strike the sparks needed to fire the gun. Pyrite has been used since classical times to manufacture copperas. Iron pyrite was allowed to weather; the acidic runoff from the heap was boiled with iron to produce iron sulfate. In the 15th century, new methods of such leaching began to replace the burning of sulfur as a source of sulfuric acid. By the 19th century, it had become the dominant method. Pyrite remains in commercial use for the production of sulfur dioxide, for use in such applications as the paper industry, in the manufacture of sulfuric acid. Thermal decomposition of pyrite into FeS and elemental sulfur starts at 540 °C. A newer commercial use for pyrite is as the cathode material in Energizer brand non-rechargeable lithium batteries.
Pyrite is a semiconductor material with a band gap of 0.95 eV. Pure pyrite is n-type, in both crystal and thin-film forms due to sulfur vacancies in the pyrite crystal structure acting as n-dopants. During the early years of the 20th century, pyrite was used as a mineral detector in radio receivers, is still used by crystal radio hobbyists; until the vacuum tube matured, the crystal detector was the most sensitive and dependable detector available – with considerable variation between mineral types and individual samples within a particular type of mineral. Pyrite detectors occupied a midway point between galena detectors and the more mechanically complicated perikon mineral pairs. Pyrite detectors can be as sensitive as a modern 1N34A germanium diode detector. Pyrite has been proposed as an abundant, non-toxic, inexpensive material in low-cost photovoltaic solar panels. Synthetic iron sulfide was used with copper sulfide to create the photovoltaic material.. More recent efforts are working toward thin-film solar cells made of pyrite.
Pyrite is used to make marcasite jewelry. Marcasite jewelry, made from small faceted pieces of pyrite set in silver, was known since ancient times and was popular in the Victorian era. At the time when the term became common in jewelry making, "marcasite" referred to all iron sulfides including pyrite, not to the orthorhombic FeS2 mineral marcasite, lighter in color and chemically unstable, thus not suitable for jewelry making. Marcasite jewelry does not contain the mineral marcasite. China represents the main importing country with an import of around 376,000 tonnes, which resulted at 45% of total global imports. China is the fastest growing in terms of the unroasted iron pyrites imports, with a CAGR of +27.8% from 2007 to 2016. In value terms, China constitutes the largest market for imported unroasted iron pyrites worldwide, making up 65% of global imports. From the perspective of classical inorganic chemistry, which assigns formal oxidation states to each atom, pyrite is best described as Fe2+S22−.
This formalism recognizes. These persulfide units can be viewed as derived from hydrogen disulfide, H2S2, thus pyrite would be more descriptively, not iron disulfide. In contrast, molybdenite, MoS2, features isolated sulfide centers and the oxidation state of molybdenum is Mo4+; the mineral arsenopyrite has the formula FeAsS. Whereas pyrite has S2 subunits, arsenopyrite has units, formally derived from deprotonation of H2AsSH. Analysis of classical oxidation states would recommend the description of arsenopyrite as Fe3+3−. Iron-pyrite FeS2 represents the prototype compound of the crystallographic pyrite structure; the structure is simple cubic and was among the first crystal structures solved by X-ray diffraction. It belongs to the crystallographic space group Pa3 and is denoted by the Strukturbericht notation C2. Under thermodynamic standard conditions the lattice constant a of stoichiometric iron pyrite FeS2 amounts to 541.87 pm. The unit cell is composed of a Fe face-centered cubic sublattice into.
The pyrite structure is used by other compounds MX2 of trans
Chalcanthite, whose name derives from the Greek and anthos, meaning copper flower, is a richly colored blue/green water-soluble sulfate mineral CuSO4·5H2O. It is found in the late-stage oxidation zones of copper deposits. Due to its ready solubility, chalcanthite is more common in arid regions. Chalcanthite is a pentahydrate and the most common member of a group of similar hydrated sulfates, the chalcanthite group; these other sulfates are identical in chemical composition to chalcanthite, with the exception of replacement of the copper ion by either manganese as jokokuite, iron as siderotil, or magnesium as pentahydrite. Other names include blue stone, blue vitriol, copper vitriol; as chalcanthite is a copper mineral, it can be used as an ore of copper. However, its ready solubility in water means that it tends to crystallize and recrystallize as crusts over any mine surface in more humid regions. Therefore, chalcanthite is only found in the most arid regions in sufficiently large quantities for use as an ore.
Secondarily, due to its rich color and beautiful crystals, is a sought after collector's mineral. However, as with its viability as an ore, the solubility of the mineral causes significant problems. First, the mineral absorbs and releases its water content, over time, leads to a disintegration of the crystal structure, destroying the finest specimens, it is critical to store specimens properly to limit exposure to humidity. Second, higher quality crystals can be grown synthetically, and, as such, there is a concern that disreputable mineral dealers would present a sample as natural when it is not. Given that chalcanthite is found in oxidized copper deposits, it is found in association with other copper minerals. Associated minerals include: Calcite and its polymorph, both CaCO3 Brochantite, Cu46 Chalcopyrite, CuFeS2 Malachite, Cu22 Melanterite, FeSO4 · 7H2O Chalcanthite's blue color is one of its most notable features, but it is insufficient in identification. Other useful tests include associated minerals, crystal habit and subsequent coloring of the water blue.
Chalcanthite can dye materials blue when dissolved in water, has a peculiarly sweet and metallic taste, although consuming it can induce dangerous copper poisoning. Copper sulfate Mineral Galleries
Van Duzen River
The Van Duzen River is a river on the north coast of California. It is a major tributary of the Eel River and drains 429 square miles in Humboldt County, with a small portion in Trinity County; the river travels 63 miles from its headwaters on the west side of the North Coast Range to its confluence with the Eel River, about 14 miles upstream from the Pacific Ocean and 17 miles south of Eureka, California. The river's elevation is over 5,000 feet at its source and only 60 feet when it merges with the Eel River; the river has two forks in its upper reaches. The North Fork travels northwest until it reaches the small town of Dinsmore, where it starts flowing west; the Little Van Duzen, which flows northwest, joins the North Fork a few miles later. The river flows west from on, it meets Yaeger Creek, about 5 miles before it reaches the Eel River. The river is used for recreation at locations including Grizzly Creek Redwoods State Park and for industrial and municipal water supply by residents living along the western portion of California State Route 36.
The river provides wildlife habitat for preservation of rare and endangered species including cold freshwater habitat for fish migration and spawning. The primary land use in the watershed is timberland. Road construction and poor logging practices historical, have increased erosion, leading to excessive sediment buildup in the river and its tributaries. In addition, gravel mining at the confluence of the Van Duzen and Eel River, has increased erosion, affected channel alignment and may block fish migration. About 26 percent of the land is owned by industrial timber companies. About 31 percent is owned, but not industrial, land used for timber production and ranches. Residential land makes up 26 percent and public land makes up 17 percent. Most of the public land is near the river's headwaters in Six Rivers National Forest; the Van Duzen River has been federally designated as a "National Wild and Scenic River". It is named for James Van Duzen a member of the Josiah Gregg exploring party that first traveled to Humboldt Bay overland in 1849.
United States Environmental Protection Agency Klamath Resource Information System U. S. Geological Survey Geographic Names Information System: Van Duzen River, USGS, GNIS Friends of the Van Duzen River
Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical formula CuFeS2, it has a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black. On exposure to air, chalcopyrite oxidises to a variety of oxides and sulfates. Associated copper minerals include the sulfides bornite, covellite, digenite. Chalcopyrite is found in association with native copper. Natural chalcopyrite has no solid solution series with any other sulfide minerals. There is limited substitution of Zn with Cu despite chalcopyrite having the same crystal structure as sphalerite. Minor amounts of elements such as Ag, Au, Cd, Co, Ni, Pb, Sn, Zn can be measured substituting for Cu and Fe. Selenium, Bi, Te, As may substitute for sulfur in minor amounts. Chalcopyrite is present with many ore-bearing environments via a variety of ore forming processes. Chalcopyrite is present in volcanogenic massive sulfide ore deposits and sedimentary exhalative deposits, formed by deposition of copper during hydrothermal circulation.
Chalcopyrite is concentrated in this environment via fluid transport. Porphyry copper ore deposits are formed by concentration of copper within a granite stock during the ascent and crystallisation of a magma. Chalcopyrite in this environment is produced by concentration within a magmatic system. Chalcopyrite is an accessory mineral in Kambalda type komatiitic nickel ore deposits, formed from an immiscible sulfide liquid in sulfide-saturated ultramafic lavas. In this environment chalcopyrite is formed by a sulfide liquid stripping copper from an immiscible silicate liquid. Chalcopyrite is the most important copper ore. Chalcopyrite ore occurs in a variety of ore types, from huge masses as at Timmins, Ontario, to irregular veins and disseminations associated with granitic to dioritic intrusives as in the porphyry copper deposits of Broken Hill, the American cordillera and the Andes; the largest deposit of nearly pure chalcopyrite discovered in Canada was at the southern end of the Temagami Greenstone Belt where Copperfields Mine extracted the high-grade copper.
Chalcopyrite is present in the supergiant Olympic Dam Cu-Au-U deposit in South Australia. Chalcopyrite may be found in coal seams associated with pyrite nodules, as disseminations in carbonate sedimentary rocks. Crystallographically the structure of chalcopyrite is related to that of zinc blende ZnS; the unit cell is twice as large, reflecting an alternation of Cu+ and Fe3+ ions replacing Zn2+ ions in adjacent cells. In contrast to the pyrite structure chalcopyrite has single S2− sulfide anions rather than disulfide pairs. Another difference is. Copper metal can be extracted from the roasting of chalcopyrite, as shown in the following reaction: 2CuFeS2 + 5O2 + 2SiO2 ⇌ 2Cu + 4SO2 + 2FeSiO3 Although if roasted it produces Cu2S and FeO. Classification of minerals List of minerals Kesterite
Copiapite is a hydrated iron sulfate mineral with formula: Fe2+Fe3+462·20. Copiapite can refer to a mineral group, the copiapite group. Copiapite is a secondary mineral forming from the weathering or oxidation of iron sulfide minerals or sulfide-rich coal, its most common occurrence is as the end member mineral from the rapid oxidation of pyrite. It occurs with fumaroles, it occurs with melanterite, fibroferrite, botryogen and amarantite. It is by far the most common mineral in the copiapite group, it occurs as single crystals, is in the triclinic crystal system, is pale to bright yellow. It is soluble in water, changing the water color to deep orangish-red. In solution copiapite is acidic. In high concentrations a negative pH can occur, as reported in waters draining from Richmond Mine at Iron Mountain, California. Copiapite can be distinguished from native sulfur because it does not give off an odor when dissolved in water, it can be distinguished from similar appearing uranium minerals, such as carnotite, by its lack of radioactivity.
The only way to differentiate between the minerals in the copiapite group is by X-ray diffraction. Copiapite was first described in 1833 for an occurrence near Copiapó, Chile, it is sometimes known as yellow copperas. Other occurrences are in California, in the filled paleo sinkholes and caves of Missouri. Classification of minerals List of minerals