To see a world in a grain of sand and heaven in a wild flower, hold infinity in the palm of your hand and eternity in an hour. -William Blake. Your spirituality is on display with Tanzanite infinity jewelry. Tanzanite is the new birthstone of December and has a unique purple-blue color. A tanzanite ring is one of the newest fashion trends and is a must for any jewelry collection. The birthstone of December, the intense deep blue color of a london blue topaz ring can evoke thoughts of warm Caribbean nights.