9.0 on the Mohs scale.

Myanmar (Burma), Thailand, India, Sri Lanka (Ceylon), Tanzania, Afghanistan, Australia, Brazil, Cambodia, Malagasy Republic, Malawi, Pakistan, Zimbabwe (Rhodesia), United States (Montana, North Carolina).

Sapphires are found in a variety of colors. The reddish colors are called ruby. People generally think of sapphires as blue in color, although they are also colorless, pink, orange, green, golden, yellow, purple and black. Sapphire is the birthstone of the month of September. Red sapphires are known as ruby, and pinkish orange sapphire as padparadscha.

Sapphire is always heat treated to produce, intensify or lighten color and/or improve color uniformity and appearance. Heat treatment of sapphires is performed at the sapphire mines, and is a industry-wide accepted practice. We have had a lot of requests for untreated sapphires, but they don't exist. Unless you dig it out of the ground yourself, always assume that any sapphire is heat treated.

More information on gemstone enhancements.