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Corundum and the Peridotites of Western North Carolina
Joseph Hyde Pratt,Joseph Volney Lewis
Keine Leseprobe verfügbar - 2018
Corundum and the Peridotites of Western North Carolina (Classic Reprint)
Joseph Hyde Pratt
Keine Leseprobe verfügbar - 2018
abrasive abundant alteration amount amphibole amphibolite analysis appearance associated belt blue border brown Buck Creek character chemical chlorite chromite Clay County cleavage closely color considerable constituent contains Corundum Hill County crystalline crystals deposits described developed diameter dikes dunite east emery enstatite entirely extends feet feldspar formation frequently garnet gems Geol gneiss grains green hardness hornblende inches iron irregular known lamination less light localities Macon County magnesia magnetite masses massive material mica Microscopic miles mineral mining Mountain nearly North Carolina observed occurs olivine origin outcrop oxide parallel peridotite places planes plates portions present probably quantity region relations represented River rock ruby Sapphire schists secondary separated serpentine shown side similar sometimes specimens spinel structure surface Survey talc thickness thin trace usually varies variety various vein wheel zone
Seite 337 - ... which exhibit the following order of formations : " (1) Chrysolitic rock somewhat mixed with anthophyllite ; (2) a layer of micaceous rock; (3) a seam of chalcedony; (4) a stratum of chloritic rock (ripidolite) ; (5) the same through which the corundum is regularly diffused sometimes in narrow veins or widening out to several feet.
Seite 338 - He calls attention to the occurrence of corundum chiefly in chlorite veins and says: "The chlorite seems to have been first crystallized; and then the alumina, of which the corundum is composed, was evidently in a state of solution and must have permeated the chlorite either in thermal waters or steam.
Seite 342 - ... held in solution in the molten mass of the peridotite when it was intruded into the country rock and that it separated out among the first minerals as the mass began to cool.
Seite 386 - ... hydrous magnesium silicate known as chrysotile. It was the former of these minerals that was originally used commercially, but as the chrysotile began to be used for the same purposes it was placed on the market under the same name. While these minerals are equal in their heat-resisting properties, the chrysotile is superior in strength and elasticity of fiber to any variety of amphibole asbestos. The former mineral is usually greenish-white, green, yellowish to brownish in color, and has a decidedly...
Seite 90 - Total 0.23 0.11 0.03 0.30 Trace 100.36 crops. . . . Transparent colorless, allotriomorphic olivine grains constitute the mass of the rock. Chromite in scattering crystals or irregular grains is a constant accessory .... In the great majority of cases, even when the hand specimens look perfectly fresh, the olivine is found to have altered somewhat to serpentine, with sometimes more or less talc, chlorite, etc. Hence the olivine grains are usually completely separated from one another by these secondary...
Seite 197 - ... in syenites and other igneous rocks, as well as in various gneisses and schists. It has been found in many crystalline rocks, and in some of them as an original mineral, but...
Seite 391 - ... have a maximum length, as thus far observed, of three-fourths of an inch, varying from this down to not more than one-sixteenth of an inch. It is similar in all respects to the Canadian product, and is just as good in quality. The other variety occurs upon the slickensided surfaces that are common to serpentine, and the fibers form layers of varying thickness against these surfaces, and have been found varying in length from a fraction of an inch up to 3 or 4 inches. These seams or layers of...
Seite 196 - In this process, which is also called the silicate process, silicate of soda is used as the binding material. The silicate is thoroughly mixed with the emery or corundum and some drying material and tamped into molds. It is then subjected to an '
Seite 399 - CARPENTER, GEORGE W. On the Mineralogy of Chester County, with an account of some of the Minerals of Delaware, Maryland and other Localities.
Seite 230 - A series of scattering deposits extends the peridotite belt through this State in a northeast direction, passing in a general way up the valley of the Chattahoochee river to the western extremities of North and South Carolina. Along this line, corundum has been found in the following counties : Rabun, Towns, Union, Lumpkin, Habersham, Hall, Cobb, Paulding, Douglas, Carroll, Heard, Troup, and somewhat off the line to the east, in Walton. One occurrence is reported in Forsyth county in a region of...