STAR RUBY!!! A rare variety of ruby that exhibits asterism; a six-rayed star(sometimes 12) that shimmers over the surface of the stone when it is moved. Ruby is classified as the red form of gem-quality corundum. Corundum is the second hardest mineral with a hardness rating of nine. Its superior hardness combined with its rich color and silky shine, fine quality ruby is classed as one of the group of four so-called "precious" stones, along with diamond, emerald and sapphire
