December has four birthstones which represent a variety of blue hues. Turquoise is the traditional option, Tanzanite, Zircon, and Blue Topaz are modern additions. See this post from the GIA on the December birthstones: here
December has four birthstones which represent a variety of blue hues. Turquoise is the traditional option, Tanzanite, Zircon, and Blue Topaz are modern additions. See this post from the GIA on the December birthstones: here