Natural red chalk, also called sanguine, is a dry earth pigment, a red ochre variety of haematite that has been known for thousands of years. It was used by the ancient Egyptians and ancient Romans for wall painting. As a drawing medium, it did not become as popular as black chalk until the 16th century. Leonardo da Vinci, at the end of the 15th century, was the first major artist to use it, and his example was quickly followed. It became popular on its own and in combination with other media, particularly black chalk. It was found in a number of European locations (e.g. the mountains of Germany in Vasari’s day), the colour ranging from warm blood-red to a darker cooler red depending on the mineral’s origins. Being usually harder than black chalk, it was suitable for small, tight drawings. It could also, however, be smudged for broad, soft effects, wetted to make a dark solid line or ground up and diluted with water for use as wash. Because it is inherently lighter in tone, it allowed greater subtlety in the gradations, and, given its closeness to flesh tones, it was the perfect medium for figure and head studies (for illustration of Michelangelo’s red chalk