Magnetite Iron Spangle

Iron Spangle - Magnetite Fe3O4
Used to produce blacks and speckles in glazes (1-5%)
A mineral form of black iron oxide. When mixed in clay body or glazes, produces a speckling effect. (Should be screened due to inconsistent particle sizes.)
The final colour obtained with iron oxide varies with the type of glaze, firing temperature and kiln atmosphere.
Iron oxide is also an active flux in glazes and even in small amounts will make a glaze noticeably more fluid.