What it is
Hematite: iron(III) oxide, Fe₂O₃, one of the most abundant iron ores on Earth and one of the oldest minerals worked into jewellery and pigment. Its defining properties are hardness and weight, 5.5–6.5 on the Mohs scale, roughly level with hardened steel, and density is the first thing most people notice: it is heavier in hand than a stone its size has any right to be.