hematite

views updated May 08 2018

hematite (haematite, iron glance, kidney ore, red iron ore, specularite) Iron mineral, Fe2O3; one of the main ores for iron; sp. gr. 4.9–5.3; hardness 5–6; trigonal; steel-grey to black, often iridescent, compact varieties dull to bright red; red to reddish-brown streak; metallic lustre; crystals tabular or rhombohedral with curved, striated faces, also occurs as columnar, mammillated, and botryoidal masses; no cleavage; widely distributed as an accessory mineral in igneous rocks, hydrothermal veins, as a rock-forming mineral in sedimentary rocks, as a primary mineral, as concretions or a cementing agent, and as a replacement for other minerals. Bedded ores of hematite form huge deposits in the Precambrian of N.America and elsewhere. See BANDED IRON FORMATION (BIF).

hematite

views updated May 17 2018

he·ma·tite / ˈhēməˌtīt/ (Brit. hae·ma·tite) • n. a reddish-black mineral consisting of ferric oxide. It is an important ore of iron.

hematite

views updated May 23 2018

hematite One of the most important iron ores, containing mainly ferric oxide, Fe2O3. Containing 70% iron by weight, it occurs in several forms and from steel-grey to black in colour.