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
Creamy Zircon Ring