Ruby is a red gemstone that is often used as a stone in rings. It's called a ruby because of its color, hardness, and how it was formed: by crystallization of corundum (aluminum oxide, which can form...
Ruby is a red gemstone that is often used as a stone in rings. It's called a ruby because of its color, hardness, and how it was formed: by crystallization of corundum (aluminum oxide, which can form...