"Hematite, also spelled as haematite, is a common iron oxide with a formula called Fe2O3 and has been widespread in rocks and soils. Hematite forms in the shape of crystals through the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at temperatures above 950 °C (1,740 °F).
Hematite is colored black to steel or silver-gray, brown to reddish-brown, or red. It is mined as the main ore of iron. Varieties include kidney ore, martite (pseudomorphs after magnetite), iron rose and specularite (specular hematite). While these forms vary, they all have a rust-red streak. Hematite is harder than pure iron, but much more brittle. Maghemite is a hematite- and magnetite-related oxide mineral." - (en.wikipedia.org 01.03.2020)
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