Ruby is a kind of pink to blood red gem. It is a variety of mineral corundum (alumina). Other varieties of gem grade corundum are also called sapphires. Ruby, together with Amethyst, sapphire, emerald and diamond, is one of the main traditional gemstones. They say rubies come from Rubi, Latin red. The color of rubies is attributed to chromium.

The quality of a ruby depends on its color, cut and clarity, and the weight of the carat affects its value. The brightest and most valuable red tone is called blood red or pigeon blood, which is much higher than other ruby of similar quality. After the color becomes clear: like diamonds, transparent stones will prevail, but rubies without any needle like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone of July, usually more pink than garnet, although some rhyolite garnets are similar in color to most rubies. The most expensive ruby in the world is the sunrise ruby.