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11 Fun Facts about Opal

By Caitlyn Learman


Opal is an incredibly beautiful and mysterious stone, whose origins are still largely disputed in the jewellery industry! Believed to promote kindness, love, compassion, and generosity, it is a stone loved by many! Here are some interesting facts you may not know about this rainbow-coloured stone.

  • Opal is the official birthstone for October and is traditionally gifted as a 14th-anniversary gift.
  • Australian opals are considered to be some of the finest quality opals in the world, and the country supplies approximately 95 to 97% of the world's opal supply! Opal can also be found in Brazil, Ethiopia, Hungary, Mexico, Nicaragua, Peru and the United States.
  • The word opal comes from the Latin word "opalus" which means precious stone.
  • Opal is made of hydrated silica and can contain as much as 20% water. If left out in a very warm environment, they can actually dry up and become damaged!
  • The formation process of opal is widely disputed, but many believe that silica is carried down into rock crevices by heavy rains. Once the water evaporates, a silica gel is left in its place that then hardens over the course of what some believe is millions of years!


  • Opals rank 5.5 to 6.5 out of 10 on the Mohs Scale of Hardness. They are very delicate stones and require a little extra care to ensure that they stay in one piece!

  • Petrified wood has the same makeup as an opal, given they are both formed from amorphous silica. However, not all petrified wood can be classified as opal.
  • Opal doublets have been quite common since the early 1970s. A doublet is made by taking an opal that has been sliced and adhered to onyx or other gem material to give the illusion of a bigger, dark, more expensive stone.
  • In November 1906, Miner Charlie Dunstan discovered an incredible opal that is now referred to as "The Fire Queen", which weighed roughly 6.5oz and measured out to be close to 900ct! The magnificent stone was eventually sold in the 1940s to J.D. Rockefeller, who then donated it to his family collection.

  • The "Aurora Australis" is considered to be the world's most valuable black opal. This stone was also discovered by Charlie Dunstan in 1938 in Lightning Ridge. The stone is now on display at the Altman and Cherney showroom in Sydney, Australia.

  • The "Andamooka Opal" or the "Queens Opal" was a gift for Queen Elizabeth II in honour of her royal visit to Australia in 1954. This can be viewed in Buckingham Palace's collection of crown jewels.

Looking to add some fiery opals to your jewellery collection? Take a look at our selection on 100 Ways!