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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1912 Excerpt: ...sometimes becomes their chief constituent. Most commonly associated with crystalline metamorphic rocks, also frequently in rocks that are rich in ferromagnesium minerals, such as diabase, gabbro, peridotite. In many cases forms large ore bodies that are thought to be the result of magmatic differentiation; such bodies are often highly titaniferous. Occurs at times in immense beds and lenses, inclosed in old metamorphic rocks. Found in the black sands of the seashore. Occurs as thin plates and dendritic growths between plates of mica. Often intimately associated with corundum, forming the material known as emery. In the United States, found in large beds with the Archsean rocks of the Adirondacks in Warren, Essex and Clinton counties of northern New York; in various places in New Jersey; at Cornwall, Pennsylvania. Important foreign localities are in Norway and Sweden, where it is the chief iron ore. Natural magnets or lodestones are found in Siberia; in the Harz Mountains, Germany; at Magnet Cove, Arkansas. Name. Probably derived from the locality Magnesia, bordering on Macedonia. A fable, told by Pliny, ascribes its name to a shepherd named Magnes, who first discovered the mineral on Mount Ida by noting that the nails of his shoes and the iron ferrule of his staff adhered to the ground. Use. An important iron ore. Franklinite. Composition. (Fe, Zn, Mn)0.(Fe, Mn)2O3. Shows wide variation in the proportions of the different elements present, but conforms to the general formula, R0.R2O3. Crystallization. Isometric. Habit strongly octahedral. Dodecahedron sometimes as truncations. Other forms rare. Crystals often rounded. Structure. Massive, coarse or fine granular, in rounded grains or crystallized. Physical Properties. H.= 6. G.= 5.15. Metallic hasten Color iron

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