December - the birthstones for December are Blue Topaz and Turquoise.
Blue Topaz is the hardest of the silicate minerals. While pure Topaz is colorless, minor changes of elements within the stone result in a variety of other colors, such as blue, pale green, red, yellow and pink.
The blue hue is created when Topaz is heated, whether the heat source is natural or engineered by man. The three shades of Blue Topaz are Sky, Swiss and London Blue. The latter is the deepest blue and is often used as a less expensive substitute for Sapphire.
Topaz is found primarily in Brazil, Nigeria, Sri Lanka, Mexico, Pakistan, China, and the United States.
Turquoise was originally named because it was initially brought to Europe by way of Turkey, this stone is one of the first gems to be used in jewelry. Turquoise was considered by ancients to be a sacred stone, protective against all manners of evil and ill health. This beautiful gemstone is mined in Iran and the southwestern United States. Turquoise is a copper aluminum phosphate mineral with a hardness of 5 to 6. It may be one of the longest used of all gemstones. The Egyptians were mining turquoise in the Sinai as far back as 3200 B.C.The name peridot most probably derives from the Arabic word "faridat" for gem. It's also called chrysolith (derived from the Greek word "goldstone") and olivine, because of its color and membership to the olivine group.