Beware of Terminology: Red Sapphire vs. Ruby; What is the Difference?

The easiest way to distinguish the two is by starting with an understanding of Sapphire.

Sapphire is the fancy name for the naturally occurring translucent mineral Corundum. The varying colors of Sapphire come from imperfections in the mineral.

A Ruby is formed when Corundum has an imperfection of chromium. This gives a ruby its deep red color. So, then what is Red Sapphire?

Red Sapphire does not occur naturally. It is formed when a piece of Corundum is infused with beryllium and subjected to intense heat and pressure. This causes an ordinary Sapphire to take on a reddish hew.