Black Opals: Everything You Need To Know + Evaluation Guide

There are arguably no gemstones out there that are quite as enigmatic as the black opal. Despite its name, the black opal exudes striking arrays of rainbow color, flashing patterns of fire and opulence that put them in a league of their own.

It was Shakespeare himself who deemed the black opal “The Mother of All Gemstones” and we aren’t going to argue with Shakespeare now, are we?!😃

This unique gemstone is a stunning added touch to any fine jewelry and will certainly set you apart from the crowd. This rare and eye-catching gemstone has made its mark on the hearts of jewelry lovers worldwide.

Black Opal Stone on Gray Blackground

Basics: What is a black opal?

Alright, let’s start with the basics so we know exactly what we’re working with here!

Black opal origins and history

Black opals are so exceptionally rare that these show-stopping gemstones are found in one place; Australia.

Even more specific than that, most opals are generally found in the small town of Lightning Ridge which only has a population of roughly 2,000 people!

Australia is responsible for approximately 90% of the world’s opal market and because of the rarity of these stones, it’s more important than ever that they are mined ethically and responsibly⁠—once they’re gone, they’re gone!

Whilst Australian black opal is perhaps the most well-known (and where the birth of black opal all began) we must not forget the emergence of Ethiopian black opal which was first discovered in 1990's.

Today, Ethiopia is considered the second-largest opal-producing area on the market.

Ethiopian Opal
Also known as "Welo Opal" named after the Wollo Province of northern Ethiopia!

How are they formed?

Australia by its very nature is what allows these black opals to form.

Let’s talk science! These black opals are created with a combination of silicon dioxide and water. Water transports silica through the earth, where it is deposited in cracks, nooks, and crannies in the earth’s crust.

As the water evaporates, the chemical deposit is left behind, and over years and years of pressure—an opal is formed.

The black opal increases in rarity due to its elusiveness to mining experts. There are no real clues that help these miners in their quest to find the next lot of beautiful black opals, all they can do is get digging and hope for the best!😚

Black opal appearance

As mentioned above, black opals—despite their name—are not necessarily black. “Potch” is a natural backing that gives the black opal its dark body color which makes for a beautifully contrasting backdrop for the rainbow colors to dance against.

No gemstone has mastered light diffraction the way opals have.

Unlike other gemstones that get their colors when specific elements are present during the formation process—the main element in opal is the same as the one found in glass, silica.

During the process of creation, the water evaporates leaving stacked spherical deposits of silica which leaves gaps between the spheres. Light passing through these gaps splits and forms the vibrant colors of the rainbow.

This is why the black opal is anything but black.

Halley’s Comet Opal
According to the Guinness Book of World Records, Halley’s Comet Opal is the largest uncut black opal in the world! Founded at Lightning Ridge, Australia (as expected) it was mined in 1986, the year Halley’s Comet was seen from earth.

It weighs a whopping 1,982.5 carats and is the size of a grown man’s fist!

How to evaluate the value of black opals?

Opals are quite unique in that, of all of the gemstones, it has its own specific specifications that we must take into account to determine the overall quality of the opal.

The jaw-dropping black opal is in a league of its own, so it’s only appropriate that we evaluate them carefully looking at the following criteria:

Body Tone

When it comes to black opals the darker the body tone, the better! The body color of a black opal can range from black through to very light grey.

The darker and more intense the body color, the more rare the stone. And you know what that means?! The more valuable it is considered to be.

We can measure the body tone on a scale that ranges from N1 (being the darkest) and N9 (being the lightest). In reference to this, N1 is the most highly desired body tone for a black opal because when matches with a vibrant play of color it provides depth and richness like no other!


Brilliance is the term used to specify the richness and clarity of color an opal displays when viewed in the face-up position.

When discussing the brilliance of color, we’re really trying to avoid a dull and lifeless-looking display of color from the opal. We want boldness! We want vibrancy! We want to see the opal color from over a meter away!

The brilliance scale ranges from B1 (most bright and brilliant opal) to B7 (least brilliance and relatively dull opal). B1 as you might imagine is what we’re looking for!

Play of Color

For all opals, including the black opal, the play of color is all-important. And the play of color focuses on how the flashes of iridescent color play with the light as the opal is moved and seen from angles.😇

With the black opal, we want to be able to see it from every kind of angle or be able to move the light source and not see any disparity in the play of color.

The rainbow colors should be evenly distributed across the stone. The entire crown of the opal should clearly display fire that is distributed evenly across the stone.


Transparency can get a little tricky where opals are concerned because, depending on the type of opal, different levels of transparency are preferable.

But we are talking about black opal today!

And where black opals are concerned it is desirable to have a more opaque background. Why? Because the depth of darkness in the body tone is what allows the rainbow colors to really dance across the stone.

The contrast of an opaque black background is of great benefit to the black opal.


As with all opals, the black opal can be found with a vast array of color patterns that offer a truly unique aesthetic. Some are rarer than others and some more desirable, however, where the pattern is concerned it is arguable that this really comes down to personal preference!🤗

Here are some of our favorite opal color patterns:

  1. Harlequin opal - features the appearance of color in either rectangular or diamond shapes.
  2. Contra-luz - Only shows play of color when a light source is directly behind the stone
  3. Cat’s Eye opal - Exhibits a thin line of bright white light, similar to that of a cat’s eye.
  4. Pinfire Opal - Displays pinpoints of color throughout the stone
  5. Chinese Writing - Similar to the aesthetics of Asian scripture
  6. Floral - Large, repeated flower-shaped patterns
  7. Palette - Similar to the patterns found on an artist paint palette
  8. Peacock - Mostly blue and green colors in the style of a peacock's feather
  9. Flame - Flashes of red fire move across the surface of the stone
  10. Flagstone - Similar to Harlequin, featuring large, close sitting areas of color.
CutThe cut of opal is focused on saving as much of the rough as possible and maximizing the display of color! As always, a well-cut and well-polished black opal are more desirable precisely because it optimizes the aesthetic of the stone. Black opals are not cut into regulated shapes like other stones, they are often irregular and highly prized for their uniqueness.
ColorColor takes precedent in the evaluation of black opals. As mentioned above, we are seeking evenly distributed color, a deep body tone color, and a vibrant rainbow play of color!
ClarityAs well as transparency, clarity references the potential flaws within the opal. For the black opal, as with most gems, the fewer flaws the better! Tiny fractures are likely to occur in their formation however, those with fewer inclusions will likely command a higher price.
CaratSurprisingly, carat weight does not have a huge impact on the value of black opals. As it is the combination of all factors that determine its value. Even larger black opals can still be incredibly comfortable to wear due to their low density.

How much are black opals worth?

As you can see from the information above, the value of black opals is determined by a vast variety of factors (and we must not forget to take personal taste into account also!)✅

And this really is good news! Because it means that whilst many black opals demand a high price, we are still able to find good quality black opals on the market that are affordable for the buyer on a budget.

Loose black opal stones can range anywhere between $100 to $2500 per carat. This is all dependent on the criteria mentioned above.

With such a huge variety of shapes, sizes, colors, patterns (and all the rest!) there really is a black opal out there to suit everyone.

But, if you’re in the market for a top-quality black opal then these can easily demand a price up to $11,000.

It’s worth remembering here, however, that just because the opal is black it does not necessarily mean that it is a top-quality opal. We must always go back and examine the various evaluation factors to determine their value.

Aurora Australis
The Aurora Australis is considered the world’s most valuable black opal. Discovered at Lightning Ridge, Australia, it weighs a gargantuan 180 carats and exhibits a harlequin pattern of mostly blue, green, and red colors that contrast with the dark body. This resembles the southern lights of the Aurora Australis which gave the stone its name.

Estimated worth: $726,000USD

Fascinating black opal jewelry for your inspiration!

Now you have a better understanding of exactly how to evaluate a black opal, let’s get to the fun stuff!

The question is, how can we implement this stone into our next jewelry piece?🎈 Do the patterns and display of colors mean that we can’t wear them in our favorite jewelry pieces? You’d be surprised!

Black Opal Engagement Rings

Ah, you thought engagement rings were saved for diamonds?!

For a ring that will last a lifetime and signifies the special bond between two people, the black opal is an ideal alternative to the classic diamond.

Certainly, it will make for an exciting talking point!

For a ring with such importance and significance, you could argue that this is where one should take the opportunity to really show off their character and style.

A black opal feature stone can sit neatly on its own as a solitaire or be matched with smaller diamond accent stones to enhance its beauty and contrast with the depth of color.

Black Opal Earrings

The black opals are an exquisite option for earring decoration. Even an item as simple as the classic stud is enhanced by the play of color displayed in these little black opals.

But it doesn’t have to stop here!

If you’re looking for something more extravagant as a statement piece, then the black opals will make for an elegant pair of drop earrings for such an occasion.

The options are overwhelming!🎁

Black Opal Necklace

Black opal necklaces make for a charming and intriguing piece to compliment any wardrobe. A simple black opal pendant can easily be worn daily as a special jewelry piece that signifies personality and character.

Likewise, black opal necklaces can be quite extravagant if you’re wanting something that packs a punch! Opt for a larger pendant or a decorative piece that utilizes multiple stones and detailed metal patterns to really put your mark on it!

Everything you need to know about black opals

This guide should provide you with everything you need to know in order to make your next black opal purchase with confidence.🤟🏻

It’s easy to see why these enigmatic stones have risen in popularity over the years, adding a touch of character and personality to your jewelry box.

Whilst there are specific criteria to help you in finding a quality black opal, remember that the unique nature of every gem means that gut instinct and personal preference must be taken into account here.

If you’re looking to stand out from the crowd, the black opal is sure to hit the spot!

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