Rubies are actually a type of rare mineral called corundum. Corundum is made up of densely packed aluminium and oxygen atoms, which are colourless on their own. However, when chromium ions replace some of the aluminium, bright red hues appear in the gemstone.
Burmese warriors believed placing rubies under their skin made them invincible in battle. Although this was not the case, rubies are beaten only by diamond among the minerals, with a hardness of 9.0 on the Mohs scale.
How rubies are formed is still debated by scientists, but there are some leading theories. It is widely accepted that plate tectonics are involved, specifically where the continents of India and Asia collide to form the Himalayas.
What has baffled scientists is why rubies are present only erratically within this area’s marble. Geologists need access to Burma’s Mogok mine to prove or disprove any theory they put forward, but owing to the country’s delicate political situation, this is not currently an option.
Ruby formation theories
Some believe the key to ruby formation is salt’s presence within the limestone. This salt would have mixed with the detritus (dead organic material) and helped form the limestone that produced rubies.
Once the limestone became heated, the salt lowered the melting point of the mixture (a flux), allowing the aluminium enough mobility to mix with the chromium. Crystals of salt have been found within the ruby-containing marble, which supports this theory.
Others believe the process requires a liquid to transport silica away before rubies can develop. Silica will actually stop corundum formation, so there would be no chance of rubies forming in areas with high levels of this compound.
For most respected rubies are considered Asterick rubies or those with cat’s eye effect. The largest deposits of rubies are found in Burma, Sri Lanka, Thailand, Cambodia, India, Pakistan, Madagascar, Tanzania, Kenya, Australia, Russia, Norway and the United States.
The Asian country of Burma (now Myanmar), there is a legend how originated the first ruby. Legend says that 2,000 years ago in Burma lived dragon that was hatched three eggs. From one egg has become a Chinese emperor, another ruler of another faith, and of the third was created ruby from Burma.
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