magnetite

The mineral form of black iron oxide, Fe₃O₄, that often occurs with magnesium, zinc, and manganese and is an important ore of iron.

Magnetic oxid of iron; a black oxid of iron (Fe₃O₄ or FeO.Fe₂O₃) which is strongly attractable by a magnet.

An oxide of iron (Fe3O4) occurring in isometric crystals, also massive, of a black color and metallic luster. It is readily attracted by a magnet and sometimes possesses polarity, being then called loadstone. It is an important iron ore. Called also magnetic iron.

A magnetic mineral, Fe3O4, one of the primary ores of iron. It has also been called lodestone.

an oxide of iron that is strongly attracted by magnets