Zircon is the traditional birthstone for December.  With its high refractive index and strong dispersion Zircon has great brilliance and intensive fire.  Zircon (not to be confused with man-made cubic zirconia)  occurs in many colors including red, pink, brown, yellow, and colorless and found in many locations.

Blue Zircon Necklace
Blue Zircon Constellation Ring
Blue Zircon Studs
Creamy Zircon Ring
Gem Blue Zircon Studs