Good stone to use when focusing on planetary healing. Stone of memory, knowledge, and progress. Encourages reasoning, observation, discrenment, patience, and tact. Can eliminate pain, stress, and anger. The coloration is due to natural radiation occurring in its environment.
Crystals can also be smoky in color from the presence of sodium.
Specimens are currently found in Brazil, Switzerland, the Himalayas, and Mexico. In the U.S. sites include Arkansas, California, Nevada, and Colorado. Balances energies of mind and body. Good for meditation. Protective and grounding stone.