7.0 on the Mohs scale.

Madagascar, North America, Brazil, Myanmar (Burma), Africa, Siberia, Australia, Sri Lanka (Ceylon). Tourmaline and opal are the birthstones of the month of October. Tourmaline is the national gemstone of the United States.

There are more colors of tourmaline than any other known gemstone. The lighter colored stones are more valuable.

Refer to specific pages.

More information on gemstone enhancements.