<P> Generally, gemstone - quality corundum in all shades of red, including pink, are called rubies . However, in the United States, a minimum color saturation must be met to be called a ruby; otherwise, the stone will be called a pink sapphire . Drawing a distinction between rubies and pink sapphires is relatively new, having arisen sometime in the 20th century . Often, the distinction between ruby and pink sapphire is not clear and can be debated . As a result of the difficulty and subjectiveness of such distinctions, trade organizations such as the International Colored Gemstone Association (ICGA) have adopted the broader definition for ruby which encompasses its lighter shades, including pink . </P> <P> The Mogok Valley in Upper Myanmar (Burma) was for centuries the world's main source for rubies . That region has produced some very fine rubies, but in recent years few good rubies have been found there . In central Myanmar, the area of Mong Hsu began producing rubies during the 1990s and rapidly became the world's main ruby mining area . The most recently found ruby deposit in Myanmar is in Namya (Namyazeik) located in the northern state of Kachin . </P> <P> Historically, rubies have also been mined in Thailand, in the Pailin and Samlout District of Cambodia, as well as in Afghanistan, Australia, Brazil, Colombia, India, Namibia, Japan, and Scotland; after the Second World War ruby deposits were found in Madagascar, Nepal, Pakistan, Tajikistan, Tanzania, and Vietnam . In Sri Lanka, lighter shades of rubies (often "pink sapphires") are more commonly found . Republic of Macedonia is the only country in mainland Europe to have naturally occurring rubies . They can mainly be found around the city of Prilep . Macedonian ruby has a unique raspberry color . The ruby is also included on the Macedonian Coat of Arms . A few rubies have been found in the U.S. states of Montana, North Carolina, South Carolina and Wyoming . </P> <P> Spinel, another red gemstone, is sometimes found along with rubies in the same gem gravel or marble . Red spinel may be mistaken for ruby by those lacking experience with gems . However, the finest red spinels can have a value approaching that of the average ruby . </P>

Where are rubies found in the united states