According to the International Colored Gemstone Association, some of the oldest sapphires are located in Sri Lanka. Sapphires can be found in India, Burma, Vietnam, Thailand, Australia, Brazil and Africa. These blue gems are also discovered in large gemstone deposits in Madagascar and Tanzania.
The majority of blue sapphires seen in the world today come from either Australia or Thailand. The origin of a gem plays a significant role in determining its value, as does its color, level of transparency and size. The gem's origins also play a part in determining the color and level of color intensity of each gem.
Gems that are untreated are more valuable than those that have undergone some type of gemstone cosmetics to enhance the coloring or other facets of the gem. The most valuable sapphires are found in Kashmir, which is located between India and Pakistan, while the second most valuable sapphires come from Burma. Those from Sri Lanka rank third in value.
Sapphires belong to the group of gems called the corundum group. The corundum group is known for its high level of hardness which is second only to the diamond. Sapphires are created when pure aluminum oxide is exposed to extreme pressure and heat at a great depth. The many colors that sapphires come in are caused by the inclusion of other elements, such as iron and chrome.