Burnt sienna contains a large proportion of anhydrous iron oxide. It is made by heating raw sienna, which dehydrates the iron oxide, changing it partially to haematite, giving it rich reddish brown colour.
The pigment is also known as red earth, red ochre, and terra rossa. The first recorded use of burnt sienna as a colour name in English was in 1853.
The colour burnt sienna have been used since the introduction of Crayola drawing crayons by Binney & Smith in 1903.