Corundum

Sapphire is usually #9 on Mohs scale, excellent in toughness, but with large fractures/inclusions, or some treatments, can be less durable. Sources are Australia, Cambodia, China, India (Kashmir), Kenya, Madagascar, Myanmar(Burma), Nigeria, Pakistan, Rwanda, Sri Lanka, Tanzania, Thailand, United States, Vietnam. India is a famous, historic source of fine blue sapphire, and production is now …

Ruby is a #9 on Mohs scale, usually excellent in toughness, but with certain treatments or large fractures/inclusions can be less durable. Sources are Afghanistan, Kenya, Madagascar, Myanmar (Burma), Sri Lanka (Ceylon), Tanzania, Vietnam, and Thailand. Thailand is the world center for treatment and wholesale trade and mine production of rubies and has been declining since …