Hematite contains Fe only in the ferric state. It is the most stable iron oxide and is responsible for red pigmentations in oxidizing environments. Hematite is rhombohedral with canted antiferromagnetic structure and an additional defect magnetic moment. Above the spin–flop Morin transition temperature (262 K), the magnetization lies within the basal plane; at and below this transition, a purely antiferromagnetic structure becomes oriented perpendicular to the basal plane. The transition temperature varies with particle size, cation substitution, lattice strain, pressure, and applied field. Hematite is a weakly magnetic, high-coercivity magnetic phase with both uniaxial and triaxial magnetization switching observed at high fields. The magnetic constants and magnetic properties of hematite are known. Superparamagnetic behaviour is observed below ~28 nm; stable single domain behaviour occurs above this size to at least the tens of micron range. The multi-domain threshold size is poorly constrained, but it is large enough that most natural hematite will be in the stable single domain state and carry stable magnetizations. Hematite has a Néel temperature of ~680°C.