Art Spectrum Burnt Sienna is a dark, rich brown almost like cocoa. Burnt Sienna is one of the most ancient pigments used by humans, and it was particularly popular during the Renaissance for use in underpainting and drawing. The colour takes its name from the Italian city of Siena where the pigment was mined until the 1940s. Today it is mainly sourced from the Italian Islands of Sardinia and Sicily and the Appalachian mountains in North America. These deposits are incredibly old, dating as far back as 4.6 billion years old. Indeed, the youngest deposits are over 540 million years old.