Although the colours red and green come to mind when we think of December, it's true colours are shades of blue. December has three birthstones; turquoise, tanzanite and it's most popular blue topaz. Topaz becomes blue when it is heated, a process that can happen naturally or artificially, and results in three shades of blue that varies in its intensity. The more intense and deep the color is, the more valuable the blue topaz is, although the most deep shade, London Blue, never occurs in nature. Slight changes in the mineral composition can create hues of green, yellow or pink.
Although topaz is a very hard gemstone, an 8 on the Mohs scale of hardness, it can be split with a single blow and should be protected from harsh wear.
During the Middle Ages topaz was thought to heal both physical and mental disorders and prevent death. The Greeks believed it had power to increase strength and to make its wearer invisible while the Romans believed it had power to improve eyesight. The Egyptians wore it as an amulet to protect them from injury.
