Ruby and sapphire are varieties of the mineral corundum. - Courtesy Hamilton Jewelers Ruby is one variety of the corundum mineral species, which also includes sapphire. Ruby is highly regarded and can ...

Photos by Pooja Shirole. Bottom left: This thin section of ruby is surrounded by an isotropic reaction rim. Bottom right: A corundum granulite showing ruby with blue and pink interference colors.

Like their gemstone cousin the sapphire, rubies are just a variety of corundum, or aluminum oxide ... was rewarded with a large, deep pink ruby. This looks like a fun, quick little project ...

the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond. Corundum is ...