Perennially favored, blue is a universally adored gemstone hue. It brings to mind the open skies as well as pristine seas. No wonder cruise line passengers and others gravitate to it on their jewelry shopping excursions.
The short list for desirability in all colored stones with serious collectors includes hardness and its ability to produce an outstanding brilliance. The priciest blue hued stones include sapphire, spinel, diamonds with or without heat treatment, and tanzanite.