Ruby is the red variety of corundum; any other color variety is Sapphire. Rubies are one of only four precious gemstones; Ruby, Sapphire, Emerald and Diamond. Rubies can range in red tones, from pink or orange reds to purple reds. In the USA, a corundum must be of at least a certain red saturation to be considered a Ruby, otherwise, it must be called a Pink Sapphire. Most Rubies are from Myanmar, though many other locales have been known to produce Rubies. Almost all Rubies are treated to enhance and improve clarity, color, transparency and inclusions.