White iron pyrites

Coxcomb pyrites EINECS 235-106-8 Iron disulphide Iron sulfide (FeS2) Marcasite Radiated pyrites White iron pyrites, Iron disulfide, a mineral. The term marcasite is also occasionally applied to... 

Marcasite or white iron pyrites is the name given to a rhombic variety of pyrites which occurs m concretions, known locally as fairy balls and thunderbolts. Its crystallographic elements"are 5... 

Golden, Green, Blue, Violet, Purple, and Grey-Spongy. Also White Iron Pyrites. 

Eight or twelve-sided, white, Iron Pyrites. 

White Iron Pyrites, covered with round, white grains of Quartz, like Coriander. 

Watershed Wood Preservative 2888 White iron pyrites 1749... 

The most common type of troublesome scale is that of amorphous silica and calcium carbonate. Scales of various metallic sulphides is the rule rather than the exception. By far the most abundant sulphide scale consists of iron sulphides. They include pyrite, marcasite, and pyr-rhotite (Kristmannsdottir 1989), but sulphide scale of other metals have also been observed, such as Cu, Pb, and Zn (White et al. 1963 Gallup 1989 Gallup et al. 1995 Hardardottir et al. 2001 Reyes et al. 2002). Sulphide scales are often poorly crystalline and they may be amorphous to X-rays. Moreover, the sulphidebearing scales are known to be enriched in various elements such as Ag, As, Au, Cd, and Mn. Reyes et al. (2002) observed that scales at Rotokawa, New Zealand, also contained elevated concentrations of Hg, Sb, and Se, which were incorporated in pyrite. The quantity of sulphide scale formation is generally very limited and may in fact be beneficial rather than troublesome as the scale forms a stable protective... 

Pore-water profiles are frequently interpreted according to this concept. For example, White et ah (35) described a conceptual model of biogeo-chemical processes of sediments in an acidic lake (cf. Figure 4). They discussed the numbered points in Figure 4 as follows Diffusion of dissolved oxygen across the sediment-water interface leads to oxidation of ferrous iron and to an enrichment of ferric oxide (point 1). Bacterial reductive dissolution of the ferric oxides in the deeper zones releases ferrous iron (point 2). The decrease in sulfate concentration stems from sulfate reduction, which produces H2S to react with ferrous iron to form mostly pyrite in the zone below the ferric oxide accumulation (point 3). 

As Berner (36) pointed out in his classic work, the formation of pyrite is coupled to a process in which free sulfide is oxidized to form polysulfides, which again react with FeS to form pyrite. In this study elemental sulfur was the oxidant. However, elemental sulfur was always less than 1% of the total sulfur content in the study of White et al. (35). The findings of the experimental studies discussed on the interaction between H2S and ferric oxides (20-23), in combination with the field observations, suggest a mechanism in which ferric iron oxides are the oxidants to form polysulfides and subsequently pyrite. 

Silver is a rare element, which occurs naturally in its pure form as a white, ductile metal, and in ores. It has an average abundance of about 0.1 ppm in the earth s crust and about 0.3 ppm in soils. There are four oxidation states (0, 1 +, 2+, and 3+) the 0 and 1 + forms are much more common than the 2+ and 3+ forms. Silver occurs primarily as sulfides, in association with iron (pyrite), lead (galena), and tellurides, and with gold. Silver is found in surface waters in various forms (1) as the monovalent ion (e.g., sulphide, bicarbonate, or sulfate salts) (2) as part of more complex ions with chlorides and sulfates and (3) adsorbed onto particulate matter. 

Chalcanthite is copper sulfate, often used as a poison, and sometimes as a pigment. Melanterite is a highly poisonous product of the decomposition of pyrite and marcasite. This white powdery material can often be found on deteriorating jewelry or other items made of iron sulfides. It is mentioned here because of its extreme toxicity. 

Most mineral collections contain potentially harmful species or forms. Toxic species may be the primary components in a specimen, but they may also occur as deterioration products. An example of this is melanterite, which is a common by-product of the decomposition of pyrite and marcasite. This highly poisonous sulfate of iron occurs as a white powder or crust on decomposed specimens. 

Platinum is found in combination with arsenic as the rare mineral sperrylite, PtAs2, at Vermillion Mine in Ontario, Canada. It was first discovered by Sperry (whence its name) in 1887 along with copper and iron pyrites in contact with gold ore. It crystallises in cubes or, less frequently, in oetahedra hardness, 6-7 specific gravity, 10-602 at 20° C. It is tin-white in colour, possessed of metallic lustre, and contains traces of rhodium and antimony.4... 

Another form of iron disulphide occurs in nature as the mineral marcasitef which possesses a radiated structure and is frequently found as irregular balls on ehalky downs. When broken open the fracture exhibits a fibrous crystalline structure radiating from the centre—whence the name radiated pyrites. The fresh fracture is almost white m colour, and if quite pure the marcasite would probably be quite tin-white in appearance.7 When pure, its density at 25° C. is... 

The principal ore of arsenic (5 x 10 % of earth s crust) is arsenical pyrites, FeAsS, but the element occurs commonly with nickel, copper and tin As40g is recovered from flue-dusts collected during the extraction of these metals. Sublimation in the presence of galena, which prevents the formation of arsenites, purifies the oxide this is reduced to arsenic with carbon in a cast iron retort. The element itself has few uses about 0.5% added to lead increases the surface tension of the molten metal and allows spherical lead-shot to be produced. The principal commercial form is the so-called white arsenic, As Og. Arsenic compounds are used mainly for their toxicity arsenical insecticides have been much used. 

Al-Razi described much other equipment that would be familiar to any student of chemistry beakers, flasks, crystallizing dishes, spatulas, funnels, filters made of cloth, and pestles and mortars. His shelves contained not only all the known metals, but also many other substances such as pyrites, malachite, lapis lazuli, gypsum, hematite, galena, turquoise, stibnite, alum, green vitriol, natron, borax, salt, lime, potash, cinnabar, white and red lead, iron oxide, copper oxide, vinegar, and probably caustic soda, glycerol, and sulfuric and nitric acids. 

An iron pyrite crystal (gold color) on a white quartz crystal. 

Examples of dimorphism were known in the cases of calcite and aragonite (see p. 203), the two forms of titanium dioxide (rutile and anatase), and iron disulphide in the forms of bronze-yellow pyrites and silver-white marcasite. Mitscherlich refers to groups of isomorphous elements , such as phosphorus and arsenic. He then thought ... 

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