Outback Queensland Tours - Cunnamulla - Australia - Out The Back Australia Tours

Opal is the world's most beautiful and precious gemstones.  It is one of only six types of precious gemstones, sharing company with diamonds, rubies, sapphires, emeralds, and pearls.  Over 95% of the world's precious opal comes from Australia, and opal is revered as Australia's national gemstone.

Opal is formed from a solution of silicon dioxide and water.  As water seeps through sandstone, it picks up tiny particles of silica.  Millions of years ago, the solution flowed into cracks and voids in sedimentary and volcanic areas of inland Australia and solidified when the climate changed after the ice age. 

There are many kinds of opals however at Yowah they have Ironstone Matrix and boulders called the "Yowah Nut" and Yowah is the only place in the world "Yowah Nuts" are found. 

Yowah Nuts are ironstone concreations resembling "nuts" which contain precious opal in their centre.  Upon cracking or slicing the Yowah Nut, the precious opal is revealed.  It is interesting that no two opals are alike and each has a unique set of qualities, colours and patterns.

Matrix Opal occurs as a network of veins or infilling of voids, between grains of the host rock and in the natural state, shows fine pinfire colour.  Boulder opal matrix opal found at Yowah, which in its natural state consists of brown ironstone with small deposits of opal interspersed.