Magnetite

**Chemical name:** Ferric iron oxide

**Formula:** Fe₃O₄

**Molar mass:** 231,5 g/mol

**Hardness:** 6

**Crystal system:** Cubic system

**Cell:** Cubic face-centred arrangement of oxygen ions, the iron cations are located in the cavities.

**Crystal habit:** Octahedral.

**Information:** Magnetite is the oldest known substance having magnetic properties. In nature it forms black shiny metallic crystals. In most cases it is found as a fine crystalline granular mineral with inverse spinel structure.

**Use:** Magnetite is the best quality of iron.