hematite


Also found in: Dictionary, Thesaurus, Wikipedia.

hematite

(hĕm`ətīt), mineral, an oxide of iron, Fe2O3, containing about 70% metal, occurring in nature in red to reddish-brown earthy masses and in steel-gray to black crystalline forms. Hematite that has a metallic luster is called specular hematite, or specular iron. The red powdered hematite is used as a pigment (ocherocher
, mixture of varying proportions of iron oxide and clay, used as a pigment. It occurs naturally as yellow ocher (yellow or yellow-brown in color), the iron oxide being limonite, or as red ocher, the iron oxide being hematite.
..... Click the link for more information.
) and as rouge in polishing. Hematite is the most important ore of iron. Extensive and richly productive deposits occur in the Lake Superior region (Michigan, Minnesota, and Wisconsin) and the Birmingham district (Alabama). The mineral is widely distributed throughout the world and is responsible for the red coloration of many sedimentary rocks. See limonitelimonite
or brown hematite
, yellowish to dark brown mineral, a hydrated oxide of iron, FeO(OH)·nH2O, occurring commonly in deposits of secondary origin, i.e., those formed by the alteration of minerals containing iron.
..... Click the link for more information.
.

Hematite

 

a widely distributed ferrous mineral, Fe203, containing up to 70 percent iron. Hematite is crystallized in a trigonal system. Its crystals are steel gray with a semimetallic shine. Depending on the mineral aggregate structures and the crystallic concretion shapes, a distinction is made among (1) hematite iron glance (macrocrystalline concretions); (2) ferrous mica (flaky aggregates); (3) ferrous rosette (crystal concretions reminiscent of corollas of dog rose); (4) red ironstone (dense red microcrystallic units); (5) kidney ore (red dense reniform conglomerations); and (6) martite (dense or porous ore formations). On the mineralogical scale, the hardness is 5.5-6; the density, 5,260 kg per cu m. The powder is cherry red in color. The melting point is 1594° C.

Together with magnetite, geothite, and quartz, hematite is formed in deposits of different genetic types and in various rocks, when the oxidizing potential of the medium is sufficiently high. Hematite ores are ferrous ores of great importance, being used for smelting cast iron and steel. Iron content in solid hematite ores fluctuates from 50 percent to 65 percent. The largest deposits are connected with the oldest Precambrian ferriferous quartzites (jaspilites).

In the USSR the Krivoi Rog hematite ore deposit (in the Ukrainian SSR), the Kursk Magnetic Anomaly, and the Urals and Siberian deposits are well known. The biggest deposits abroad are situated near Lake Superior, Birmingham, and elsewhere in the USA; in the state of Minas Gerais in Brazil; and in Canada (Labrador), India (states of Bihar, Orissa, and Madhya Pradesh), and several countries of Africa.

hematite

[′hē·mə‚tīt]
(mineralogy)
Fe2O3 An iron mineral crystallizing in the rhombohedral system; the most important ore of iron, it is dimorphous with maghemite, occurs in black metallic-looking crystals, in reniform masses or fibrous aggregates, or in reddish earthy forms. Also known as bloodstone; red hematite; red iron ore; red ocher; rhombohedral iron ore.
References in periodicals archive ?
91 percent, a 'modest' mark in and of itself, but the first 'meaningful efficiency ever measured by hematite and amorphous silicon, two of the most abundant elements on Earth,' the team reported.
Second, a small amount of platinum was introduced into the hematite lattice as doping.
8 million tonne stockpile of circa 52% Fe hematite iron ore fines.
With her camera Opportunity saw hematite blueberries throughout the rocks.
They have broadly equal amounts of kaolinite, hematite, and goethite (15 25%), a high hematite/goethite ratio, and the smallest PDM component of the non-magnetic samples.
3] coating layer is transformed into a crystalline hematite coating layer by drying and calcinations processes.
a 297m long storage facility with a capacity of 255,000t which will house stockpiles of magnetite concentrate and hematite DSO delivered to port;
Analyses of samples from Australia's Marble Bar Chert--a rock formation in the northwestern part of the country--suggest the hematite there formed underwater, in the absence of UV light.
The ratio of Al substitution between goethite and hematite in the same sample is often about 2 : 1, as has been reported by several workers for diverse soil types (Anand and Gilkes 1987; Singh and Gilkes 1992a; Prasetyo and Gilkes 1994; Siradz 2000).
If it finds the layered hematite along with any carbonate species, we'll know that water had been there.
WE'RE giving every Sunday Mirror reader the chance to send off for this fantastic FREE hematite power bead bracelet.
In a red pottery sample studied, the principal coloring agent was hematite.