What makes an opal, an opal?


Opal Big

What's it made of?

Opal is the product of seasonal rains that drenched dry ground in regions such as Australia’s semi-desert “outback.” The showers soaked deep into ancient underground rock, carrying dissolved silica (a compound of silicon and oxygen) downward.

During dry periods, much of the water evaporated, leaving solid deposits of silica in the cracks and between the layers of underground sedimentary rock. The silica deposits formed opal.

Opal is known for its unique display of flashing rainbow colors called play-of-color. There are two broad classes of opal: precious and common. Precious opal displays play-of-color, common opal does not.

Play-of-color occurs in precious opal because it is made up of sub-microscopic spheres stacked in a grid-like pattern—like layers of Ping-Pong balls in a box. As the lightwaves travel between the spheres, the waves diffract, or bend. As they bend, they break up into the colors of the rainbow, called spectral colors. Play-of-color is the result. (Source:gia.edu)

How should they be cared for?

Opal is a soft stone, with approximately the same hardness as glass (around 6.5 on the Mohs hardness scale), so it is important to treat your opal carefully in order to avoid damaging it. It isn't a stone you should put on and leave on like a diamond, it's delicate, and is quite vulnerable to scratching and breaking. It is recommended that opals be removed for more physical activities like moving furniture. As well as if you're working in the garden or playing in sand it is very important to take your opal jewellery off. The tiny gritty particles will scratch against your opal, and they can even rub away the polish on the stone. 

Never allow anyone to clean your opal in an ultrasonic cleaner, as the intense vibrations may cause cracking.

Solid opal should be cleaned gently with mild detergent in warm water and a soft toothbrush or cloth. Avoid bleach, chemicals and cleaners.

If opal is delicate, is it safe to wear?

If cared for properly, opal will provide an heirloom quality brilliance that is unlike any other gem. Opals set in rings (especially claw set rings) are the most vulnerable. This is because our hands are constantly moving and get a lot of action throughout the day, creating more risk of the opal being bumped or scratched. For this reason, opal rings should be worn with care, and removed for any strenuous activity. Opals are the safest set in earrings or necklaces, as there is a very small chance of them being impacted by day to day wear.

Opal is such a unique and beautiful stone that continues to fascinate the jewellery industry today, despite its delicate form. No other gem does what opal does and that's why we believe its popularity will continue to grow for generations to come. 

Our fascination with opal dates back to early civilizations. The Romans believed that opal was the most powerful gem of all as it contained the colours of all other gems. The Bedouins believed that opal contained lightning and fell from the sky during thunderstorms. (Source: gia.edu) To this day we continue to be captivated by the kaleidoscope shift of colour and unique qualities that opal features.

Did you enjoy this blog post and want to keep reading? Check out this article to get a deeper look at Australia’s opal trade! Splendor in the Outback: A Visit to Australia’s Opal Fields


Herbin Jewellers