The Ultimate Guide for The December Birthstones Learn about the cubic zirconia, as it is even the December birthstone. So, basically, it is a crystalline form of zirconium dioxide that comes in different quality levels and price ranges. Therefore, you need to check the cut, clarity, color, and carat of the stone while buying it from an authentic store. However, this stone is faceted the same as diamonds, and a variety of cuts are used to form different shapes to get a beautiful appearance. Visit: https://www.sagaciajewelry.com/blog/december_birthstones