Sapphire deposits are found all over the world, but where do sapphires come from? Predominately in Australia, Thailand, Sri Lanka, Burma (now Myanmar), and America (Montana).
Sapphires form deep below the Earth’s surface and are brought to the surface when magma from volcanos begins to cool and crystalizes. Basaltic rocks are a large source of corundum. After the basalt is weathered away, stronger materials such as corundum (sapphires and rubies) are left behind. These minerals are then transported by rivers, creeks and streams to locations where they can ultimately be found by prospectors in the alluvial parts of water courses.
Sapphire does not occur alone in deposits. They are frequently found alongside many other gem types including, zircon, garnet, spinel, and topaz.
What kind of mineral is Sapphire
Sapphire is chemically described as Aluminium Oxide and can be minerally described as corundum. It is one of the most amazing creations of gems as it is essentially the result of soft aluminium combining with a gas (oxygen) to create one of the hardest gemstones. Sapphire measures 9 on the Mohs’ scale of hardness and is therefore one of the hardest gemstones known to man, second only to the diamond.
Corundum is heavy, in fact, it has a specific gravity of 4, meaning it has a density 4 times that of water. This is a key property for fossicking for sapphires. Similarly to gold, it allows to panner to work the sieve to encourage the heaviest of materials to fall to the bottom. So when the sieve is flipped, any sapphire should present itself on top, and be easy to see.