hematite (redirected from Kidney Ore)

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 (ocher) 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 limonite.

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hematite

 or haematite

Heavy and relatively hard oxide mineral, ferric oxide (Fe₂O₃), that constitutes the most important iron ore because of its high iron content and its abundance. Much hematite (from the Greek word meaning “blood,” for its red colour) occurs in a soft, fine-grained, earthy form called red ocher or ruddle. Red ocher is used as a paint pigment; a purified form, rouge, is used to polish plate glass. The world's largest production comes from the Hamersley Range in western Australia.