There are three birthstones for the month of December: tanzanite, zircon and turquoise. Your zodiac signs are Sagittarius (November 22-December 21) and Capricorn (December 22-January 19).
All three of these stones are a deep blue color and have their own history and chemical composition. One of the more interesting of the three is tanzanite, a gem you may not have heard of before. This rare gem is only found in Tanzania and was only recently discovered in 1967. Tanzanite gets its deep blue color from trace amounts of vanadium.
Tanzanite was discoveredby Maasai herders who were tending to the Merelani Hills around Arusha, Tanzania. These herders came across blue crystals and notified a prospector who then registered the area with the government to begin mining. The name Tanzanite was coined by Tiffany and Company who became the primary distributor of the gem and wanted to showcase the rare geographical source of this stone.