The New International Encyclopædia/Columbite
COLUM′BITE. A mineral columbate containing some manganese and crystallizing in the orthorhombic system. It has a bluish iridescence, and is of an iron-black, grayish, or brownish color. This mineral occurs in granitic and feldspathic veins in the form of crystals, crystalline granules, and cleavable masses. It is found at various localities in Bavaria, Italy, Finland, Greenland, and in the Ural region; in the United States it is found in greater or less abundance in nearly all of the States bordering along the Appalachian Mountain system, in the Black Hills of South Dakota, and in California and Colorado. It has some slight economic value for the preparation of salts of columbium and tantalum, but as only small quantities of these salts are used, the mineral is in but little demand. It is interesting to mention that the first occurrence of columbite in America was made known from a specimen sent by Governor Winthrop of Connecticut to Sir Hans Sloane, then President of the Royal Society of Great Britain.