In North Devon, England, black earth was mined in the past (until about 1967). The very black, carbonaceous mineral became the most important pigment for the navy in the 19th century in England and the USA. In the 20th century, Bideford black was used to make kohl. The mine was closed in 1963, and there are probably no remaining stocks. We were able to mine a larger quantity in the summer of 2013 and are making Bideford Black available to you. It is offered by us as a pigment and as a watercolor.
Bideford Black is a rather transparent brownish black and can be used for glazes with acrylic, watercolour, tempera and oil.
Earth Pigments in North Devon A Guide for Teachers & Artists