Opal

Opal is formed of tiny spheres of silica and the colours seen in any particular example depend upon the size and arrangement of these spheres.  They have a relatively high water content, up to 5% which means they are susceptible to dehydration and should not be kept in hot or dry conditions. The Greeks thought Opal gave powers of foresight and prophecy and the Romans believed them to be a symbol of purity and hope. 

Queen Victoria was a huge fan and not only wore them herself but gave them as gifts to each of her daughters for their weddings. The vast majority of gem quality opal is now mined in Australia; the town of Coober Pedy is a world famous source and Lightning Ridge is famed for its black Opals.

A relatively new source is the northeastern Wollo Province in Ethiopia, which became a major producer with the 2008 discovery of a large amount of white opal with a strong play of colour. The striking, bright orange-red stones that are mined in Mexico are also popular and are known as Fire Opal. 

Description: Precious opals are prized for their vivid, iridescent, rainbow colour flashes which play out against either a dark or light background, Australia is the best known source.

Hardness: 5.5 – 6.5 on Mohs Scale

Birthstone: October