Sienna is a natural earth pigment that ranges in color from reddish-brown to yellow-brown. It is derived from clay that contains iron oxide, which gives it its distinctive hue. Sienna is often used in painting and art, particularly in the Renaissance period, due to its warm tones and excellent lightfastness. There are two main types of sienna: Raw Sienna and Burnt Sienna. Raw Sienna is the unheated form, resulting in a lighter, more yellow shade, while Burnt Sienna is heated, producing a darker, richer color. Both types are popular among artists for their versatility and ability to create natural skin tones.