Red Bole in pieces

Red bole (or sanguine) is a natural mixture of hematite (responsible for its red color), quartz and feldspars, as well as other minerals. In its chemical composition this red earth is similar to ochres, though red bole is softer and more unctuous. Due to the high amount of clay minerals it contains, red bole is not suitable as a pigment, however, the amount of clay is not high enough to make it suitable as potter’s clay. This type of colored earth was formerly mined in Armenia and exported to Europe. Since ancient times, red bole has been used as drawing material. Since the end of the 15th century it was used in the form of pencils, mostly for sketches and figure drawings, often in combination with black and white chalks. Red bole can receive a high polish, thus in early Medieval times, it was used in the process of gilding.