Opal is one of those gemstones that seems almost magical — shimmering with a rainbow of colours that shift as you move it. It’s no wonder it’s often called the “Queen of Gems.” But did you know that some opal stones are worth more than diamonds? From rare black opals mined deep in Australia to enormous museum-worthy specimens, opal can reach staggering values depending on colour, clarity, and rarity.
In this guide, we’ll explore the 10 most valuable opals in the world, how opals are valued, and how you can tell if the one you own (or plan to buy) could be a treasure. Let’s uncover why this mysterious stone continues to captivate collectors and jewellery lovers across the globe.
What Is Opal?
Opal is a hydrated form of silica — essentially, a combination of silicon dioxide and water. It’s unique because of its play-of-colour, an optical effect caused by microscopic silica spheres inside the stone that diffract light into vivid rainbow hues.
Most opals are mined in Australia, which accounts for around 90% of global production according to the Gemological Institute of America (GIA). Other sources include Ethiopia, Mexico, Brazil, and the USA. Each region produces opals with distinct looks — from the bright flashes of Australian black opal to the fiery orange glow of Mexican fire opal.
No two opals are ever the same, which makes them both fascinating and valuable.
How Do You Value an Opal?
Opals aren’t valued the same way as diamonds or sapphires. Their worth depends on a combination of visual beauty and rarity. Here’s what experts look for when grading an opal:
1. Colour Play
The most important factor is the intensity and range of colours visible when the stone is moved under light. Red, orange, and violet flashes are the rarest, while green and blue are more common. Stones showing multiple bright colours are usually the most valuable.
2. Pattern
The pattern of colour distribution matters. Highly sought-after patterns include “Harlequin,” “Pinfire,” and “Flame.” The more defined and balanced the pattern, the higher the value.
3. Body Tone
The background colour — from black to white — impacts how vibrant the play-of-colour appears. Black opals, with dark body tones that make colours stand out, are typically the priciest.
4. Transparency
Crystal opals that are semi-transparent with vivid internal colours are highly prized. Opaque stones are usually less valuable unless they show exceptional brightness.
5. Origin and Size
Australian opals, especially from Lightning Ridge, are considered the gold standard. Larger stones with consistent colour play can command thousands per carat.
In fact, premium black opals can sell for over £10,000 per carat, depending on quality.
10 Most Valuable Opals in the World
Here’s a look at some of the most remarkable and valuable opals ever discovered — stones that have broken records, made history, and stunned gem lovers around the world.
1. The Virgin Rainbow – £750,000+
Discovered in South Australia, this opal is often described as “the most beautiful opal in the world.” It glows with electric colours even in darkness and measures about 6 inches long. Housed in the South Australian Museum, it’s valued at over £750,000 and is considered priceless by many experts.
2. The Olympic Australis – £1.3 Million
Weighing an incredible 17,000 carats, the Olympic Australis is the largest and one of the most valuable gem-quality opals ever found. Mined in Coober Pedy in 1956, it’s 99% pure opal, with vibrant flashes of every colour imaginable.
3. The Fire of Australia – £600,000
This 5,000-carat uncut opal, also from Coober Pedy, displays extraordinary clarity and brilliance. Experts estimate it’s around 65 million years old, making it a true geological wonder.
4. The Andamooka Opal – £400,000
Gifted to Queen Elizabeth II in 1954, the Andamooka Opal is a dazzling stone set in a diamond necklace. It features fiery flashes of red, blue, and green — the hallmark of high-grade black opal.
5. The Aurora Australis – £600,000
Found in Lightning Ridge in 1938, this 180-carat black opal is famous for its deep blue-green background and vibrant play-of-colour. Its name reflects the swirling colours of the southern lights.
6. The Halley’s Comet Opal – £400,000
Discovered in 1986, the same year Halley’s Comet passed by Earth, this 1,982-carat opal is the largest uncut black opal ever found. Its size and electric hues make it a favourite among collectors.
7. The Flame Queen – £250,000
Weighing 263 carats, this opal is instantly recognisable for its “eye-like” pattern — a rare and mesmerising feature. It’s been displayed in museums worldwide and remains one of the most iconic opals in history.
8. The Galaxy Opal – £180,000
Discovered in Brazil in the 1970s, this 3,749-carat opal is the largest black opal ever mined outside Australia. It’s aptly named for its cosmic array of colours that resemble a swirling galaxy.
9. The Pride of Australia (Red Emperor) – £200,000
This famous opal, discovered in the early 1900s, features fiery red and gold tones — incredibly rare in opal stones. It was once considered the national gemstone of Australia before it was tragically stolen in the 1950s.
10. The Black Prince Opal – £150,000
Hailing from Lightning Ridge, this opal was named for its deep, royal-blue body tone. It weighs around 181 carats and is one of the most perfectly cut opals ever documented.
How Do You Know If You Have a Valuable Opal?
Wondering if that opal pendant or loose stone in your collection could be worth something? Here’s what to look for:
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Colour Brightness – The brighter and more visible the colours, the higher the potential value.
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Even Pattern – Consistent, symmetrical colour patterns increase worth.
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Dark Base Tone – Black or dark grey opals are often more valuable than white or pale ones.
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Size and Weight – Larger, flawless stones command premium prices.
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Origin – Australian opals are generally valued higher than those from other regions.
If you’re uncertain, consider having your opal appraised by a gemologist or certified jeweller. They can use magnification and light tests to confirm authenticity and value.
Should You Buy Opal?
Absolutely — but be smart about it. Opal is not only breathtaking but also considered a solid investment. According to gemstone market data, fine-quality opals have risen in value by nearly 30% since 2018 due to limited supply and increased demand from collectors.
For jewellery, choose settings that protect the stone, such as bezels, since opal has a hardness of 5.5–6.5 on the Mohs scale and can scratch more easily than sapphires or diamonds.
If you’re new to opals, start with smaller pieces or Australian white opal jewellery — affordable yet stunning.
Conclusion
Opal isn’t just another gemstone — it’s a living display of light, colour, and nature’s creativity. From the Virgin Rainbow to the Olympic Australis, each opal tells a unique story shaped by millions of years underground.
Whether you’re drawn to opal’s history, its mystical beauty, or its investment potential, there’s no denying its allure. So the next time you spot a flash of rainbow light in a gemstone, you might just be looking at one of the world’s most valuable treasures.
FAQs
1. What’s the most expensive opal in the world?
The most expensive opal ever valued is the Olympic Australis, worth around £1.3 million.
2. Are opals rarer than diamonds?
Yes — top-quality black opals are far rarer than diamonds, especially those from Lightning Ridge.
3. How can I tell if my opal is real?
Real opals show shifting colour play when moved under light. Synthetic opals often look too uniform or have repeating patterns.
4. Can opals be worn every day?
Yes, but with care. Avoid exposing opal jewellery to extreme heat, water, or harsh chemicals.
5. Is it worth investing in opal?
Yes — especially if you focus on high-grade Australian black opals or museum-quality stones, which have consistently increased in value over time.