Blue Topaz, Turquoise, Tanzanite, and Zircon
Topaz is the birthstone for the month of December, and the stone given in celebration of the 4th and 19th anniversaries of marriage. Topaz is a symbol of love and affection, and has been said to be an aid to ones sweetness and disposition.
The December birthstone, turquoise, is regarded as a love charm. It is also a symbol of good fortune and success, and it is believed to relax the mind and to protect its wearer from harm. Turquoise rings, in particular, are thought to keep away evil spirits.
Found in just one place on earth, tanzanite is a relatively recent discovery. This blue variety of zoisite was named for Tanzania, the country where it was found, by Tiffany & Co. Because crystals show different colors depending on viewing direction, cutters can choose bluish purple or the more favored pure blue or violetish blue hue depending on how much weight they want to retain from the rough.
Zircon commonly occurs brownish red, which can be popular for its earth tones. However, most gem-quality stones are heat treated until colorless, gold or blue (the most popular color). Blue zircon, in particular, is the alternative birthstone for December.
Each gemstone associated with the month of December, the blue topaz, turquoise, tanzanite and zircon have unique characteristics that make these stones both valuable and desirable. Among the most important are the color and occurrence of the stones, making them rare and valuable.