Hematite or haematite is the main ore of iron. It is mostly iron(III) oxide. It has a metallic luster. It has no cleavage (the way a mineral breaks), but does have a fracture. The fracture is irregular and uneven. Hematite on the hardness scale is 5 to 6. It has a bright red to dark red streak. To find the streak, you take a piece of unglazed porcelain and take the mineral and run it across the plate. The colors vary from metallic gray to a dark, rough and earthy red color. Hematite has a chemical formula of Fe2O3.