The color of topaz gemstone can range from colorless to yellow, brown, pink, or blue. The most prized color for Topaz gemstone is a reddish-orange color called "Imperial Topaz". Blue Topaz gemstone is also in demand, but most blue ones on the market have undergone irradiation and heating, which is common and widely accepted in the gem industry. Topaz gemstone is found in various parts of the world, including Brazil, Russia, and Sri Lanka.