Iron Oxide Black

(Black, Fe3O4) - The varieties of irons mined - black, red, yellow - each give slightly different results. For consistent glaze effects it is best to stick with one source of iron. As a general rule, iron used in small amounts (under 1 0%) will produce browns, buff & rich reds in glazes. In larger quantities, may act as a flux. Synthetic irons are processed to meet specific standards