10.0 on the Mohs scale.

Worldwide, most notable locations are Australia, Africa, Brazil, Russia, India and most recently, Northern Canada. Diamond is the birthstone for the month of April.

Black Opaque

Diamond is occasionally to commonly laser drilled to improve appearance. Surface cavities or fractures are occasionally filled with a hardened surface. Colored diamonds are occasionally irradiated and/or heat treated to induce "fancy" colors.

More information on gemstone enhancements.

Black Diamond is a member of the Diamond gemstone family.