8.0.
Brazil, U.S., Sri Lanka (Ceylon), Myanmar (Burma), former USSR, Australia, Pakistan, Mexico, Tasmania, Japan, Africa. Topaz and citrine are the birthstones of the month of November.
American blue topaz, also known as maxi blue topaz is vivid blue and similar to swiss blue topaz. Most blue topaz is irradiated and heat treated silver topaz, although it is sometimes found naturally.
Blue topaz is usually irradiated and often heated to produce blue color.
American Blue Topaz is a member of the Precious Topaz gemstone family.