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Topic: Corundum

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	Corundum - LoveToKnow 1911
		Coarse dull corundum is found in many localities, and usually has higher commercial value as an abrasive agent than emery, which is less pure.
		The mineral has been extensively worked, as at Corundum Hill, Macon county, N. C., near which, in 1871, were discovered numerous rubies, sapphires and pebbles of coarse corundum in the bed of a river.
		Corundum occurs also at many localities in Montana, where the crystals are often of gem quality.
	www.1911encyclopedia.org /Corundum (646 words)

	CORUNDUM - Online Information article about CORUNDUM
		habit, consisting usually of the basal pinacoid with a rhombohedron, and it is notable that this habit is said to be characteristic of corundum which has consolidated from a fused magma.
		Corundum has no true deavage, but presents parting planes due to the structure of the crystal, which have been studied by Prof.
		Hyde Pratt, "Corundum and its Occurrence and Distribution in the United States," Bulletin U.S.
	encyclopedia.jrank.org /COR_CRE/CORUNDUM.html (850 words)

	Astrology & Gemstones, Birthstones: Corundum Gem for Sagittarius - Gems shop online
		Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals.
		Due to corundum's hardness, it is commonly used in as an abrasive in machining, from huge machines to sandpaper.
		There is the milky corundum, a white opaque form of corundum also called geuda, which for many years was regarded as useless and discarded, often ending up lining fish tanks.
	www.findyourfate.com /gemology/gemstones/Corundum.html (236 words)

	The mineral corundum
		In gem terms, it refers to the blue variety of Corundum, unless a color is mentioned as a prefix to sapphire (i.e.
		Translucent brown Corundum and Emery are the most common forms of Corundum.
		The industrial term "emery" describing Corundum abrasives is derived from the variety Emery which is mined for abrasive use.
	www.minerals.net /mineral/oxides/corundum/corundum.htm (685 words)

	Star Corundum
		Corundum is grown by the Verneuil technique with the addition of, preferably, 0.1 to 0.3 percent titanium oxide in the feed powder.
		The corundum as grown is clear, but develops asterism upon heat treatment at 1100 to 1500°C (Webster, 1962; Burdick et al., 1949, 1954) due to precipitation of the excess titanium, the solubility of which is exceeded at this temperature.
		The approximately flat regions obtained in Figure 2 confirm that the surrounding corundum was not contributing.
	www.minsocam.org /msa/collectors_corner/arc/star_corundum.htm (1187 words)

	Corundum (Site not responding. Last check: 2007-11-02)
		A single tabular Corundum crystal showing growth hillocks on its pinacoidal face.
		Red corundum is known as ruby, while all other colors are sapphires.
		OCCURRENCE - Corundum is found in igneous rocks that are aluminum rich and silica poor (syenites and monzonites).
	www.gc.maricopa.edu /earthsci/imagearchive/corundum.htm (167 words)

	Ruby & Sapphire: Inclusions in corundum
		Rutile in corundum tends to unmix parallel to the faces of the second-order hexagonal prism {1120}, intersecting in three directions at 60/120° in the basal plane (Sahama, 1982).
		In corundum, when the fracture was in or near the basal plane, the pockets of undigested fluid often surround hexagonal "islands" of healed material.
		Within corundum, polysynthetic twinning occurs parallel to the faces of the rhombohedron {1011}, which intersect each other at angles of 86.1 and 93.9° and meet the c axis at 32.4/57.6°.
	www.ruby-sapphire.com /r-s-bk-ch5.htm (7495 words)

	CORUNDUM Chapter 22. Oxides and hydroxides
		Corundum, an aluminum oxide mineral, was first reported from the local area by Vanuxem and Keating (1822b) and Fowler (1832).
		Corundum occurs, for the most part, as euhedral to subhedral crystals, but deformed crystals, as well as crystals whose shape is inherited in part from contact minerals, are common.
		Abundant corundum was found in the Franklin Marble immediately adjacent to the Sterling Hill orebody, associated with phlogopite, rutile, arsenopyrite, gahnite, and other minerals (Dunn and Frondel, 1990) and described herein under margarite.
	franklin-sterlinghill.com /dunn/ch22/corundum.stm (444 words)

	Reference.com/Encyclopedia/Corundum
		Corundum is a crystalline form of aluminum oxide and one of the rock-forming minerals.
		The oxygen atoms in corundum are arranged in a hexagonal close-packing, with the smaller aluminum atoms occupying ⅔ of the octahedral gaps.
		Corundum for abrasives is mined in Zimbabwe, Russia, and India.
	www.reference.com /browse/wiki/Corundum (455 words)

	corundum - HighBeam Encyclopedia (Site not responding. Last check: 2007-11-02)
		corundum, mineral, aluminum oxide, Al The clear varieties are used as gems and the opaque as abrasive materials.
		Emery is a common corundum, used as an abrasive and distinguished by its impurities of magnetite and hematite.
		The chief corundum gems are the ruby (red) and the sapphire (blue).
	www.encyclopedia.com /doc/1E1-corundum.html (475 words)

	Corundum
		Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals.
		Due to corundum's hardness (pure corundum is defined to have 9.0 Mohs), it is commonly used as an abrasive in machining, from huge machines to sandpaper.
		Corundum for abrasives is mined in Zimbabwe, Russia, and India.
	www.buzznet.com /tags/corundum (315 words)

	Corundum Mineral,Aluminum Oxide,Natural Corundum,Corundum Mineral Uses
		Corundum having a bright and glassy lustre, splintery and devoid of cleavage plane and inclusions is preferred by industry for the manufacture of superior grade abrasives.
		Corundum in small quantities is used in the manufacture of special sparking plugs, muffles, pyrometer tubes, rod and insulator for vacuum tubes of all kinds and crucibles.
		The reason for natural corundum being particularly suitable for certain kinds of grinding is its prominent basal cleavage that causes the crystal to break readily with a smooth flat surface at right-angles to the axis of elongation through successive reductions in size unlike synthetic corundum (alumina) which has a conchoidal fracture.
	www.mineralszone.com /minerals/corundum.html (640 words)

	Corundum
		Corundum is found in crystals, more or less perfectly developed, some of them 5 inches long; the pyramidal and prismatic habits are about equally common.
		Corundum does not occur in association with the zinc ores but is widely distributed in isolated pockets in the Franklin limestone.
		In the pockets the corundum is associated with one or more of the minerals spinel, rutile, graphite, edenite, pyroxene, garnet, titanite, and phlogopite.
	franklin-sterlinghill.com /palache/corundum.stm (293 words)

	Exploitation of Corundum at Lakshmipuram, Khammam District Andhra Pradesh, India.
		Corundum pieces are collected soon after the rains generally at the periphery of the basic rocks as pyroxene granulites, amphibolites and schists.
		Corundum is invariably present where the soil is underlain by brownish granule zone consisting of very small fragments of sillimanite, ferruginous matter and quartz in a matrix of brown soil.
		Corundum is reported to occur in association with the sillimanite bearing schists which are intruded at places by quartzo felspathic pegmatites.
	www.mapindia.org /2005/papers/Geology/61.htm (1648 words)

	Ultramafic-Related Corundum - Mineral Deposit Profiles, B.C. Geological Survey
		Corundum is commonly found in quartz-free reaction zones located along contacts of silica-deficient rocks, such as ultramafic and mafic rocks, with pegmatite, paragneiss, syenite gneiss or other felsic rocks.
		In marundite, corundum occurs as coarse hexagonal crystals embedded in scaly or rosette-shaped aggregates of margarite.
		As well, the solid inclusions within corundum crystals, corundum texture, and associated minerals in the concentrates may be indicative of the type of primary source, such as gem corundum hosted by alkalic rocks (Q10), corundum in aluminous metasediments (P16) and gem corundum in marbles.
	www.em.gov.bc.ca /Mining/Geolsurv/MetallicMinerals/MineralDepositProfiles/profiles/q09.htm (1980 words)

	Corundum - Sapphire & Ruby are both Corundum
		Red corundum and most pink corundum is called ruby, blue corundum is called sapphire, and other colours are also called sapphire, usually with the colour specified as a prefix to the word sapphire, for example, yellow sapphire.
		Pure corundum is colourless, often called white, and although quite rare, tends not to be valuable because it does not have much brilliance.
		Corundum is very hard, having a hardness of 9 on Moh's scale, compared with 10 for diamond, and 8 for topaz.
	www.24carat.co.uk /corundum.html (306 words)

	corundum.htm (Site not responding. Last check: 2007-11-02)
		Corundum survives erosion and weathering, and can be found as a heavy mineral in sands and gravels.
		CHIPPEWA COUNTY: Corundum is sparsely found as tiny grains in the Barron quartzite in the Blue Hills east of Rice Lake (Ernst et.
		RUSK COUNTY: Corundum is sparsely found as tiny grains in the Barron quartzite in the Blue Hills east of Rice Lake (Ernst et.
	www.uwrf.edu /~wc01/corundum.htm (255 words)

	Mineral description : Corundum (Site not responding. Last check: 2007-11-02)
		Blue to yellow corundum in andesin and surrounded by a rim of margarite.
		As corundum is so hard it is often found in placer deposits.
		Corundum appears as a transformation zone around kyanite together with oligoclase.
	www.geology.neab.net /minerals/corundum.htm (274 words)

	Gems.gr
		Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals.
		Corundum is mined in Russia, India and Zimbabwe.
		Emery grade corundum (an impure variety of corundum) is found on the Greek island of Naxos.
	www.ship.gr /gems/s_cor.htm (51 words)

	Corundum Factsheet and Information Page at mineralminers.com
		Corundum is characterized by its high hardness, luster and specific gravity, and its color and habit.
		Corundum that has been synthetically manufactured from bauxite is most often used for this purpose.
		Corundum is said to enhance one's creativity, self-confidence, awareness, intuition and ambition.
	www.mineralminers.com /html/corminfo.htm (1625 words)

	Ruby (corundum), What is Ruby (corundum)? About its Science, Chemistry and Structure
		Ruby is the gem quality of the mineral corundum, one of the most durable minerals which exists, a crystalline form of aluminium oxide.
		Corundum has a hardness of 9 on the Mohs scale and is also extremely tough.
		All colors of corundum except red are known as sapphires, which has created controversy about where ruby ends and sapphire begins, particularly in pink shades of corundum.
	www.3dchem.com /molecules.asp?ID=78 (1344 words)

	Atlanta Gemologists: Corundum & Gemologist in Atlanta, Georgia
		Corundum can be colorless, red, pink, blue, fl, brown, orange, yellow, green, indigo, violet, or mauve.
		Red corundum is called ruby, blue corundum is called sapphire, and other colors are also called sapphire, usually with the color specified as a prefix to the word sapphire, for example, yellow sapphire.
		Pure corundum is colorless, often called white, and although quite rare, tends not to be valuable because it does not have much brilliance.
	www.therossjewelrycompany.com /atlanta.gemologists.gemologist.corundum.html (364 words)

	Corundum main page
		Sapphire is commonly used to denote blue corundum, with others named according to color, e.g.
		Corundum is a relatively common mineral that once found wide application as an industrial abrasive.
		Corundum was the first gem mineral to be synthesized in the lab by a process known today as flame fusion.
	www.geo.utexas.edu /courses/347k/redesign/gem_notes/corundum/corundum_main.htm (4456 words)

	Corundum
		Corundum forms a minor component of a number of metamorphic rocks, marbles and schists, but also of granite, pegmatite, syenites, and others.
		Corundum is very hard, and it is often mined from so-called secondary deposits like river gravels, where the Corundum is preserved even if the rest of the rock has decomposed.
		Corundum is stable in a normal household environment - it is one of the most stable and inert minerals known.
	www.hedegaard.com /Minerals/Species/Corundum.html (1314 words)

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