History
In 1912, the "modern" birthstones were decided by Jewelers of America. The birthstones they chose for December are blue topaz and turquoise. In 2002, tanzanite was also made a December birthstone by the American Gem Trade Association.
Identification
Topaz, an aluminum fluorosilicate, is rarely found blue in nature. It is commonly irradiated to produce a blue color. Turquoise is a green-blue aluminum copper phosphate. Tanzanite, a hydrated calcium aluminosilicate, is heat treated to bring out a bluish-violet color.
Geography
Topaz is mined in New Hampshire, Utah, California, Pakistan, Nigeria, Namibia, Australia, Russia and Brazil. Turquoise is found in Turkey, Israel, Egypt, China, Iran, Afghanistan, Tibet, Russia, Armenia, Africa, Chile, Brazil, Mexico, Arizona, California, New Mexico, Colorado and Nevada. Tanzanite is mined in Tanzania, mainly near Mount Kilimanjaro.
Significance
The Romans thought topaz improved eyesight, and the Greeks thought it made the wearer invisible and strong. Egyptians thought it protected the wearer from injury. Turquoise is considered a sacred stone among certain Native American tribes. Tanzanite, found in 1967, has no lore. There is, however, a story that the gem was originally found after a lightning fire by Masai herders.
Other Birthstones
Other common birthstone systems still used include the traditional, mystic and Ayurvedic systems. The December birthstones for these systems are lapis lazuli, clear zircon and white zircon; onyx, and ruby, respectively.