Many ancient cultures believed that Opals gave the gift of foresight, and all of them prized it as a lucky gem. Fire Opal has a bright yellow, orange or red background, not to be confused with the play of colour precious opal often referred to as having ‘fire’.Īrabian legends believe that Opals fell from the heavens in flashes of lightning, whereas the Greeks believed they were the tears of Zeus after he won a battle against the Titans.The Aborigines believed that Opals were in fact their creator god, the Rainbow Serpent, and the Indians believe Opal was their Goddess of Rainbows, who turned herself into the gem in order to escape the unwanted advances of the other gods. The most desired precious Opal comes from Australia and can fetch thousands of dollars per carat, whilst other famous localities include Ethiopian Welo Opal, Oregon, Mexico and Virgin Valley. Precious Opal is typically black or white and is graded on the colour flash displayed. Common opal comes in a variety of colours such as greens, pinks, blues and white but does not display any flash or “play of colour”. There are three main categories of Opal – common, fire and precious. The colour comes from the tiny Silica spheres that make up the crystal, and they have to be arranged in a certain way and be a certain size to create the colour flashes. These two things make it a mineraloid rather than a mineral - amber and obsidian are two other famous non-crystal ‘mineraloids’. It is a hydrated form of Silicon Dioxide - basically Quartz with added water! As the water content can vary depending on the opal, this means it does not have a fixed chemical composition either. Opal is technically not a crystal as it is amorphous - it does not have a defined crystal structure.

Opal properties