Types of Opal at a Glance: Every Opal Compared
One family, countless faces
Types of opal are many, and hardly any gemstone is as varied as opal. Where each type comes from, how they differ, and which one suits you best, you'll see here at a glance.
Explore the world map, compare the types side by side, and jump straight to each detailed profile.
Trade names and mineralogy don't run in parallel. Precious opal and common opal share the formula SiO2 with n H2O. What separates them is order: only neatly arranged silica spheres diffract light into shifting spectral colors. Anything without that fire remains common opal, even when the stone is beautiful and genuine.
The second axis is body tone, in Australia often graded N1 (nearly black) to N9 (light). Transparency runs perpendicular to it: crystal means translucent, regardless of the N value. That's why Crystal White and Black Crystal exist in the same mine. The third axis is the host rock. Boulder takes ironstone along with it, matrix spreads opal through the pores, and solid opal is the closed seam with no backing.
Origin is the fourth axis, not a type of its own. Australia stands for sedimentary precious opal, historically the lion's share of the market. Ethiopia (Welo) stands for volcanic, often hydrophane opal with plenty of fire at a lower price. Mexico stands for fire opal, whose orange is often body color. Saying “Australian opal” doesn't yet tell you whether the stone is black, light, boulder, or crystal.
The cut follows the rough. Freeform keeps more fire, round and oval sell more easily, and faceting is the exception. The piece counts beneath the icons reflect our shop inventory on a given date, not the world market and not a rarity statistic.
Where does precious opal come from?
Tap a region. The map zooms in and shows you the types of opal found there.
Tap a region above to see its types of opal.
Australian opals
Black OpalDark base, the most intense fire
White OpalThe light classic, delicate to vivid
Boulder OpalOn ironstone, very durable
Crystal OpalSee-through, fire from the depths · Lightning Ridge
Ethiopian opals
Welo OpalNeon-like fire, hydrophane
Mexican opals
Fire OpalWarm body color, can be faceted
Water OpalGlass-clear hyaliteArticle coming soon
Opal from Honduras
Honduran OpalOpal in black basalt matrixArticle coming soon
How are types of opal classified?
Many well-known names aren't a type of their own but umbrella terms. The most important distinction comes first:
- Milk opal
- Hyalite / water opal
- Honey opal
- Wood opal
- Moss opal
Within precious opal, stones are grouped by origin (Australian, Ethiopian, Mexican) and by appearance: crystal opal refers to transparency, harlequin opal to the pattern, matrix opal to the stone being intergrown with its host rock. The cut is not a type: round, oval, teardrop, heart, marquise, and freeform are cabochon shapes. Faceting remains the exception because it breaks up the fire. The piece counts beneath the icons reflect our shop inventory, not the world market.
Don't confuse construction with type. Opal doublets and opal triplets are layered stones, often with a dark backing and a quartz cap. They can imitate any pattern and are worth less than solid opal. When in doubt, check the side edge: a straight line means glue.
“Water opal" has two meanings: usually the glass-clear Mexican hyalite, but colloquially also the clear Ethiopian Welo opal.
Three types mentioned less often
Beyond the six major types above, there are forms that show up less often in the trade but regularly cause confusion. Two of them are distinct varieties in their own right; one, strictly speaking, isn't precious opal at all.
Matrix Opal
Here the opal material sits finely dispersed in the pores of the host rock instead of forming a closed layer. The play-of-color appears as a network of dots and veins. Important: some of the material on the market has been blackened, and that must be disclosed.
Girasol
A translucent opal with a milky, bluish glow that drifts across the stone as you turn it. It shows no true play-of-color, only this single sheen. That's why it's occasionally mistaken for moonstone.
Honey Opal
Warm yellow to amber and usually translucent, with no play-of-color. It counts as a common opal and is prized for its body color, not for fire.
The difference that matters: Precious opal shows play-of-color, meaning shifting colors created by light diffraction. Common opal such as honey opal has only a body color. Both are genuine opal, but only play-of-color drives the price. Why that is, you'll find in What is an opal.
Compare types of opal directly
Tap the types you're interested in and see them side by side. The widget doesn't replace the text: black versus white is body tone, Welo versus Lightning Ridge is origin plus hydrophane behavior, fire opal versus precious opal is body color versus diffraction.
Your opal comparison
On your phone, two fit side by side; from the third on, you can scroll sideways.
Frequently asked questions about types of opal
How many types of opal are there?
There are a handful of major types of precious opal, such as black, white, boulder, Welo, crystal, and fire opal. On top of that come many names that describe an origin or appearance rather than a distinct type.
What is the most valuable type of opal?
Black opal from Lightning Ridge in Australia. Its dark base makes the play-of-color glow more intensely than in any other opal.
Is “Australian opal" a type of opal in its own right?
No, it's an umbrella term for origin. Black opal, boulder opal, white opal, and crystal opal from Lightning Ridge are all Australian opals.
What's the difference between precious opal and common opal?
Precious opal shows the famous play-of-color; common opal doesn't. A pure milk opal, for example, only shimmers, without the dancing fire inside.
Which type of opal is the most affordable?
White opal is the most common and most affordable precious opal. Ethiopian Welo opal is also an accessible way in, with plenty of play-of-color.
What is a water opal?
Usually the glass-clear, transparent Mexican opal (hyalite). Colloquially, though, clear Welo opal from Ethiopia is called that too.
If you're unsure or have questions, feel free to reach out anytime, even if you didn't buy your opal from us. Contact form, email hello@libertyangelsjewelry.com or call: +1 310 591 9778.
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Only natural, genuine opals. Every certificate is linked to your order online and therefore tamper-proof.
Written by Anton Kehler
Founder of FAERELLI & Liberty Angels
