Iron Pigments:

• Yellow Ochre: a naturally occurring clay of monohydrated ferric oxide (Fe₂O₃.H₂O)

Red pigments

Iron oxide pigments:

• Red Ochre: anhydrous Fe₂O₃
• Burnt Sienna: a pigment produced by heating Raw Sienna.

Brown pigments

Clay earth pigments (naturally formed iron oxides)

• Raw Umber: a natural clay pigment consisting of iron oxide, manganese oxide and aluminum oxide: Fe₂O₃ + MnO₂ + nH₂O + Si + AlO₃. When calcined (heated) it is referred to as Burnt Umber and has more intense colors.
• Raw Sienna: a naturally occurring yellow-brown pigment from limonite clay.