sulphide ores

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classification of sulphide ores and about some four of them


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The members of the Sulfide Class form an economically important class of minerals. Most major ores of important metals such as copper, lead and silver are sulfides. Strong generalities exist in this class. The majority of sulfides are metallic, opaque, generally sectile, soft to average in hardness and they have high densities, black or dark colored streaks and an igneous origin. But, there are a few vitreous and transparent members such as realgar, cinnabar and orpiment that tend to break the mold, so to speak. Minerals belonging to the selenide, telluride, antimonide and arsenide subclasses have very similar properties to the more common sulfides. The whole or partial supplanting of sulfur by either selenium, tellurium, antimony, arsenic or bismuth is possible because these elements have similar sizes, charges and ionic strengths. Only minerals in the sulfide class that have no appreciable sulfur are included in these subclasses. Except in the case of the Sulfosalts. This is a large segment of the sulfide class whose difference from the other sulfides lies in the position of the semi-metal ions.

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CLASSIFICATION: Acanthite/Argentite (Silver Sulfide) Aguilarite (Silver Selenium Sulfide) Alabandite (Manganese Sulfide) Argentopentlandite (Silver Iron Nickel Sulfide) Argentopyrite (Silver Iron Sulfide) Argyrodite (Silver Germanium Sulfide) Arsenopyrite (Iron Arsenic Sulfide) Bismuthinite (Bismuth Sulfide) Bornite (Copper Iron Sulfide) Carrollite (Copper Cobalt Nickel Sulfide) Chalcocite (Copper Sulfide) Chalcopyrite (Copper Iron Sulfide) Cinnabar (Mercury Sulfide) Cobaltite (Cobalt Arsenic Sulfide) Covellite (Copper Sulfide) Cubanite (Copper Iron Sulfide) Digenite (Copper Sulfide) Famatinite (Copper Antimony Sulfide) Galena (Lead Sulfide) Germanite (Copper Germanium Gallium Iron Zinc Arsenic Sulfide) Gersdorffite (Nickel Arsenic Sulfide) Glaucodot (Copper Iron Arsenic Sulfide)

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Greenockite (Cadmium Sulfide) Hauchecornite (Nickel Bismuth Antimony Sulfide) Hauerite (Manganese Sulfide) Jalpaite (Silver Copper Sulfide) Kermesite (Antimony Oxysulfide) Laurite (Ruthenium Sulfide) Lautite (Copper Arsenic Sulfide) Linnaeite (Cobalt Sulfide) Marcasite (Iron Sulfide) Metacinnabar (Mercury Sulfide) Millerite (Nickel Sulfide) Molybdenite (Molybdenum Sulfide) Orpiment (Arsenic Sulfide) Patronite (Vanadium Sulfide) Pentlandite (Iron Nickel Sulfide) Polydymite (Nickel Sulfide) Pyrite (Iron Sulfide) Pyrrhotite (Iron Sulfide) Realgar (Arsenic Sulfide) Rheniite (Rhenium Sulfide) Schollhornite (Hydrated Sodium Chromium Sulfide)

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Subclass: Sulfosalts Aikinite (Lead Copper Bismuth Sulfide) Andorite (Silver Lead Antimony Sulfide) Baumhauerite (Lead Arsenic Sulfide) Berthierite (Iron Antimony Sulfide) Boulangerite (Lead Antimony Sulfide) Bournonite (Lead Copper Antimony Sulfide) Chalcostibite (Copper Antimony Sulfide) Cylindrite (Iron Lead Tin Antimony Sulfide) Subclass: Selenides* Berzelianite (Copper Selenide) Clausthalite (Lead Selenide) Eucairite (Silver Copper Selenide) Klockmannite (Copper Selenide) Tiemannite (Mercury Selenide) Umangite (Copper Selenide) Subclass: Tellurides* Altaite (Lead Telluride) Calaverite (Gold Telluride) Coloradoite (Mercury Telluride) Empressite (Silver Telluride) Hessite (Silver Telluride) Kostovite (Copper Gold Telluride) Krennerite (Silver Gold Telluride) Melonite (Nickel Telluride) Nagyagite (Gold Lead Antimony Iron Telluride Sulfide) Petzite (Silver Gold Telluride) Rickardite (Copper Telluride) Sylvanite (Silver Gold Telluride) Subclass: Antimonides* Aurostibite (Gold Antimonide) Breithauptite (Nickel Antimonide) Dyscrasite (Silver Antimonide) Subclass: Arsenides* Domeykite (Copper Arsenide) Lollingite (Iron Arsenide) Maucherite (Nickel Arsenide) Nickeline (Nickel Arsenide) Nickel-skutterudite (chloanthite) (Nickel Arsenide) Rammelsbergite (Nickel Arsenide) Safflorite (Cobalt Iron Arsenide) Skutterudite (Cobalt Arsenide) Smaltite (Cobalt Nickel Arsenide) Sperrylite (Platinum Arsenide) Siegenite (Cobalt Nickel Sulfide) Sphalerite (Zinc Iron Sulfide) Stannite (Copper Iron Tin Sulfide) Sternbergite (Silver Iron Sulfide) Stibnite (Antimony Sulfide) Stromeyerite (Silver Copper Sulfide) Teallite (Lead Tin Sulfide) Tetradymite (Bismuth Tellurium Sulfide) Tungstenite (Tungsten Sulfide) Ullmannite (Nickel Antimony Sulfide) Wurtzite (Zinc Iron Sulfide

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Dufrenoysite (Lead Arsenic Sulfide) Emplectite (Copper Bismuth Sulfide) Enargite (Copper Arsenic Sulfide) Franckeite (Lead Tin Iron Antimony Sulfide) Freieslebenite (Silver Lead Antimony Sulfide) Geocronite (Lead Antimony Arsenic Sulfide) Gratonite (Lead Arsenic Sulfide) Hutchinsonite (Thallium Lead Arsenic Sulfide) Jamesonite (Lead Iron Antimony Sulfide) Jordanite (Lead Thallium Arsenic Antimony Sulfide) Matildite (Silver Bismuth Sulfide) Meneghinite (Copper Lead Antimony Sulfide) Miargyrite (Silver Antimony Sulfide)

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Owyheeite (Silver Lead Antimony Sulfide) Polybasite (Silver Copper Antimony Sulfide) Proustite (Silver Arsenic Sulfide) Pyrargyrite (Silver Antimony Sulfide) Sartorite (Lead Arsenic Sulfide) Schapbachite (Silver Bismuth Sulfide) Semseyite (Lead Antimony Sulfide) Smithite (Silver Arsenic Sulfide) Stephanite (Silver Antimony Sulfide) Tennantite (Copper Arsenic Sulfide) Tetrahedrite (Copper Iron Antimony Sulfide) Wittichenite (Copper Bismuth Sulfide) Wittite (Lead Bismuth Selenide Sulfide) Xanthoconite (Silver Arsenic Sulfide) Zinkenite (Lead Antimony Sulfide)


FORMATION OF SULFIDE ORES Sulfide ore deposits are a type of which are associated with and created by volcanic-associated hydrothermal events in submarine environments. They are predominantly stratiform accumulations of sulfide minerals that precipitate from hydrothermal fluids on or below the seafloor in a wide range of ancient and modern geological settings. In modern oceans they are synonymous with sulfurous plumes called black smokers. They occur within environments dominated by volcanic or volcanic derived. As a class, they represent a significant source of the world's Cu, Zn, Pb, Au, and Ag ores, with Co, Sn, Ba, S, Se, Mn, Cd, In, Bi, Te, Ga and Ge as co- or by-products. Massive sulfide deposits are forming today on the seafloor around undersea volcanoes along many mid ocean ridges. Mineral exploration companies are exploring for seafloor massive sulfide deposits; However, most exploration is concentrated in the search for land-based equivalents of these deposits.

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THE MINERAL CINNABAR Chemistry: HgS, Mercury Sulfide Class: Sulfides and Sulfosalts Uses: primary ore of mercury, a pigment and as a Specimens Cinnabar is a colorful mineral that adds a unique color to the mineral color palette. The twinning in cinnabar is distinctive and forms a penetration twin that is ridged with six ridges surrounding the point of a pryamid. It could be thought of as two scalahedral crystals grown together with one crystal going the opposite way of the other crystal. Cinnabar was mined by the Roman Empire for its mercury content and it has been the main ore of mercury throughout the centuries. Some mines used by the Romans are still being mined today. Cinnabar shares the same symmetry class with quartz but the two form different crystal habits.

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PHYSICAL CHARACTERISTICS: Color -- bright scarlet or cinnamon red to a brick red. Luster -- adamantine to submetallic in darker specimens. Transparency -- translucent to transparent. Crystal System -- trigonal; 32 Crystal Habits-- individual, well formed, large crystals are scarce; crusts. It also forms modified rhombohedrons, prismatic and twinned crystals as discribed above. Cleavage -- perfect in three directions, forming prisms. Fracture --uneven to splintery. Hardness -- 2 - 2.5. Specific Gravity -- 8.1+ (very heavy for a non-metallic mineral) (approx.) Streak -- red Associated Minerals are realgar, pyrite, dolomite, quartz, stibnite and mercury. Other Characteristics-- silghtly sectile and crystals are striated. Notable Occurances --Almaden, Spain; Idria, Serbia; Hunan Prov., China and California, Oregon, Texas, and Arkansas, USA. Best Field Indicators -- crystal habit, density, cleavage, softness and color.

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Chemistry: Ag3SbS3, Silver Antimony Sulfide Class: Sulfides Subclass: Sulfosalts Uses: an ore of silver and as mineral specimens. Specimens: Pyrargyrite is a popular silver bearing mineral for collectors. Its color is a dark red and is most commonly so dark that it appears black. The nickname "Ruby Silver" has been applied to pyrargyrite. Pyrargyrite is the more common of the two minerals and is usually found in the same ore veins with proustite, silver and other silver sulfides. Its crystals can be striking and very attractive. It is reactive to light and can darken upon exposure, and a translucent specimen can quickly become essentially opaque. Therefore, fine specimens should be stored in closed containers with exposure to light limited. PYRARGYRITE

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Color --dark red to red-black. Luster -- adamantine. Transparency -- crystals are translucent to nearly opaque. Crystal System -- trigonal; 3m Crystal Habits -- prismatic crystals with rhombohedral and scalenohedral faces forming terminations. There is no perpendicular mirror plane and therefore a hemimorphic crystal can be seen, in some rare examples, with differing terminations at the top and bottom of the crystal. Typical crystals are poorly formed and modified heavily by secondary faces. Also found massive. Cleavage -- sometimes distinct in three directions forming rhombohedrons. Fracture -- conchoidal. Hardness -- 2.5 Specific Gravity -- 5.8 (very heavy for translucent minerals) approx. Streak -- dark cherry red. Associated Minerals -- proustite, silver, tetrahedrite, calcite, argentite. quartz, galena, sphalerite and other silver vein minerals. Other Characteristics -- darkens upon exposure to light and crystals are frequently striated. Notable Occurances -- Atacama, Chile; silver mines in Saxony Germany and in Colorado, USA and Cobalt, Onatario, Canada. Best Field Indicators -- crystal habit, density, association with silver sulfides and color. PHYSICAL PROPERTIES

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Chemistry: MoS2, Molybdenum Sulfide Class: Sulfides and Sulfosalts Uses: major ore of molybdenum and as mineral specimens Specimens Molybdenite is a very soft metallic mineral. It can be easily confused with graphite molybdenite has a bluish-silver color and streak. Molybdenite's structure is composed of molybdenum ions sandwiched between layers of sulfur ions. The sulfur's layers are strongly bonded to the molybdenum, but are not strongly bonded to other sulfur layers, hence the softness and perfect cleavage. It is soft enough to leave a mark on paper and fingers. Its greasy feel is due to its extreme softness. Molybdenite or "Moly Ore" as it is sometimes called, is a very high luster mineral. MOLYBDENITE

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PHYSICAL CHARACTERISTICS: Color -- silver metallic with a bluish cast. Luster -- metallic. Transparency -- crystals are opaque. Crystal System -- hexagonal; 6/m2/m2/m Crystal Habits -- thin, platy hexagonal crystals terminated by pinacoidal faces, also as tapering six-sided pyramids that can be truncated by the pinacoids. Also massive, lamellar and in small grains in sulfide ore bodies and recrystallized marbles. Cleavage -- perfect in one direction, forming thin sheets. Fracture -- flaky. Hardness -- 1.5 - 2. Specific Gravity -- 4.7 to 4.8 (average for metallic minerals) Streak -- bluish gray.

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ACANTHITE Chemistry: Ag2S, Silver Sulfide Class: Sulfides Uses: An ore of silver and as mineral specimens. Specimens Acanthite is the most important silver ore next to galena. most important silver ore. Acanthite is often confused with the name argentite and it is no wonder. Several mineral guides interchange the names or combine the names as is done here. But the proper mineral name when referring to Ag2S at room temperatures is acanthite. Argentite is a name applied to one polymorph of Ag2S. Acanthite and argentite have the same chemistry , Ag2S, but different structures. Argentite has an isometric structure and is only stable at temperatures above 173 degrees Celsius and if cooling from a melt, will form isometric crystals such as cubes, octahedrons and dodecahedrons. Upon cooling to below 173 degrees Celsius, argentite transforms from its isometric structure to the monoclinic structure of acanthite..

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Color -- lead gray to black. Luster -- metallic. Transparency -- Crystals are opaque. Crystal System -- Monoclinic; 2/m below 173 degrees Celsius (acanthite) and isometric; 4/m bar 3 2/m above (argentite). Crystal Habits -- rarely well formed pseudo: cubes, octahedrons and dodecahedrons. Non-argentite crystals (those that formed below 173 degrees Celsius) of acanthite tend to be of a slender prismatic habit. More commonly found massive and as coatings or as arborescent (branching) and reticulated groups. Cleavage -- absent. Fracture -- conchoidal. Hardness -- 2.5 - 3 Specific Gravity -- 5.5 - 5.8 (slightly heavy even for metallic minerals) approx. Streak -- shiny black. Other Characteristics -- Sectile, meaning it can be cut with a knife like lead and fresh shiny surfaces will eventually form a dull coating after prolonged exposure to light (can be removed by ultrasonic treatment). Associated Minerals -- silver, quartz, bornite, gold, galena, proustite, pyrargyrite, stephanite and other silver sulfide minerals. Notable Occurrences -- Guanajuato, Mexico; Freiberg and Saxony, Germany; Cobalt, Ontario, Canada; Comstock Lode, Nevada and Butte, Montana, USA; Cornwall, England; Chile; Peru; Bolivia and especially Kongsberg, Norway. Best Field Indicators a-- crystal habit, density, softness, sectility, association with other silver sulfosalts and color. PHYSICAL CHARATERISTICS

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