Ochre, Yellow

Yellow Ochre – Fe₂O₃H₂O Limonite (m.p. 2415^o F/1325^o C) is common in earthenware clay sources (rarely used in glazes as a colorant) and is one of the primary yellow or buff colorants in raw clay. It contains iron and manganese. When fired, the molecular bound water evolves off and forms Red Iron Oxide (Fe₂O₃). It is a significant source of red color in earthenware clay bodies. Used in Engobes as a colorant to produce ochre yellow, tans, and browns. Naturally occurring Yellow Ochre is less expensive than manufactured Yellow Iron Oxide.