Rubies like to grow in a flat, hexagonal shape,  and are found classically in India. Recently, Sri Lanka, Pakistan, and Afghanistan have exposed substantial Ruby deposits. In Southeast Asia, Myanmar, Thailand, Cambodia, and Vietnam have also been long regarded as sources of fine Rubies.
Ruby is made up of the mineral corundum, which is aluminum oxide (alumina, Al2O3). It becomes the precious stone when it has a a small impurity of chromic oxide which gives it the rich red color. If the corundum has other impurities to give it other colors, it is called sapphire.
It has been associated with improved energy and concentration, creativity, loyalty, honor and compassion.
Ruby is a birthstone for July.