| Molybdenite and corundum are also found in the schist through which the elvan dykes have cut. |
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| This is, of course, ludicrous because corundum and quartz are mutually exclusive. |
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| Also on a hillside to the north is a contact metamorphosed bed rich in small, dark blue, platy corundum crystals. |
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| He also found particles of gemstones such as corundum, garnet, rutile, and argentite. |
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| First, to prove beryllium could diffuse into corundum and create a color change, he heated pink sapphires with beryllium and got yellow rims. |
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| Reports of gem-quality corundum are rare in Wyoming, although both ruby and sapphire have been noted. |
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| The grayish-blue, partly gemmy cordierite, when first discovered in the early twentieth century, was mistakenly reported as corundum. |
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| Thus, further investigations of Wyoming's vermiculite deposits may lead to the discovery of other corundum occurrences. |
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| In Wyoming, corundum has been found in gneiss, pelitic schist, and vermiculite schist. |
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| Although blue corundum, zircon, and tourmaline occur in Colorado, they are not known to produce gems. |
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| All granites are peraluminous as implied by the ubiquity of normative corundum. |
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| Chapters 2-19 describe eighteen specific traditional gemstones or families, beginning with corundum and ending with rhodonite. |
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| The surface is rough-blasted with corundum, after which a hydroxylapatite coating is applied to it. |
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| In addition, poor-quality, translucent to cloudy, dark gray cordierite is also present, as is corundum with well-developed rhombohedral parting that tends to crumble. |
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| Diamond has been assigned a hardness value of 10, only a single point higher than corundum on Mohs scale, although it is far harder than this would indicate. |
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| One of these occurs at Baggot's Rock, where specks of corundum are found. |
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| Moreover, corundum and periclase have not been detected in space dust before. |
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| Aluminum oxide exists in several different crystallographic forms, of which corundum is most common. |
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| He called the new compound Carborundum because the natural mineral form of alumina is called corundum. |
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| Following the ceramic production process, Al2O3 is present in the thermodynamically stable crystal modification corundum. |
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| Grinding sets made of agate and sintered corundum are not suitable for cryogenic grinding. |
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| Treibacher belongs to the Austrian Wienerberger-Konzern and is active in the manufacture and sale of corundum. |
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| Slightly harder than quartz but less so than corundum and diamond, the emerald owes its high value to its colour and transparency. |
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| These products, also known as corundum, are obtained by fusing alumina or bauxite in an electric arc furnace. |
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| A pink-red corundum is most often called ruby, while any other shade of pink corundum will be called a sapphire. |
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| Somewhat surprisingly, tiny crystals were found with rhodolite garnet and corundum during alluvial gem mining in streams draining Mason Mountain, Macon County, North Carolina. |
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| Most natural corundum is of industrial quality, but transparent to translucent varieties with their adamantine to vitreous luster potentially yield gemstones. |
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| In the 1980s, geologists in Moscow found several small diamonds and minerals, such as zircon, garnet, and corundum, in the alluvia of the River Karla. |
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| Next in line, at 9 is corundum, which is a generic name for sapphire. |
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| The corundum runs no risk for one's health. |
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| Variety of corundum, gem of a bright red and birthstone of July. |
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| Wienerberger group of companies is active in the production of systems for walls and roofs made out of bricks, tiles and clinkers, silicium carbide and synthetic corundum. |
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| Kyanite, garnet, monazite, and amphibole are common minerals, while apatite, anatase, titanite, corundum, pyroxene, and epidote are rare. |
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| Heavy cotton fabric, full resin bond with corundum. |
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| Grinding sets of tungsten carbide, stainless steel, zirconium oxide or sintered corundum may be used since no direct cooling of the grinding set takes place! |
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| This mix-corundum is a product made of ceramic grinding wheels and corundum powder from the abrasives industry and therefore it is a high-quality blend of conventional corundum and aluminium oxide. |
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| If these react chemically with each other, nanocrystals form, such as silicon carbide, silicon oxide, corundum and even diamond, as is already known from the examination of meteorite that have formed from such dust. |
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| There are number of natural and synthetic materials which could be used in place of garnet for abrasive purposes such as staurolite, diamond and corundum among others. |
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| What is the blue variety of the mineral corundum better known as? |
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| Corundum occurs as an accessory mineral in some metamorphic rocks, such as mica schist, gneiss, and crystalline limestone. |
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