Ruby vs Sapphire: Two Colors of Corundum

Ruby and sapphire are both corundum, one of the hardest natural minerals. Chromium creates ruby's red, while iron and titanium give sapphire its classic blue.

Sapphire also comes in pink, yellow, green, and the rare pink-orange padparadscha. Only red corundum is called ruby.

Both rank 9 on the Mohs scale, which makes them excellent for rings and other jewelry you wear every day.