LIMONITE (from Gk. Xabo marshy. meadow), or FlRoWN HEMATITE. The hydrated sesquioxide of iron (2Fe,O,31-1,0), con taining 59.89 per cent. of metal. When pure or nearly so, it occurs in compact masses with a silky or submetallie lustre, brown or brownish yellow, in color, and a hardness of 5-5.5 on the mineral scale; but when mixed with clay. as it often is, it is found in the form of a loose ochreous earth, colored various shades of yellow or brown. Limonite is a commercial source of iron, but by no means the most important one Large de posits are found in Alabama and Virginia, and it is known in other States. especially those of the Appalachian region. It is mined to some extent in Europe. The ore occurs frequently in superficial deposits found by the weathering of pyritiferous and other ores, or else as nodular masses scattered through beds of ferruginous day, and firmed perhaps by deposition from waters which have circulated through and leached the adjacent rocks. A form of ore called 'bog-ore' is found in the beds of lakes, ponds. and marshes, where it has been precipi
tated from the water by the oxidizing action of the air. In some countries, notably Sweden. the bog-ore accumulates to a thickness of half a meter every fifteen to thirty years, and is peri odically dredged out. Owing to the admixture of so much clay, limonite rarely forms a high-grade ore. The production of limonite in the 'United States in 1901 amounted to 3,016.715 long tons.
BIBLIOGRAPHY. Penrose, "The Chemical RelaBibliography. Penrose, "The Chemical Rela- tion of Iron and \langanese in Sedimentary Rocks," 'Journal of Geology, vol. i. (('hicago, 1893) ; Peebin, "Virginia Oriskany Iron ()re'," Engineering and Mining Journal, vol. liv. (New York, 1892) ; McCalley, "The Limonites of Ala bama Geologically Considered." Engineering aad Mining Journal, vol. lxii. (New York, 189r,); ilopkins, "Limonite Ores of Pennsylvania," Bul letin Geological Society of America, vol. xi. (1Zochester, See IRON; lion IlloN ORE; OCHRE; .31INERAL PAINTS.