Opal: Meaning, Properties, Uses & Value

The first opal I ever bought was a lie.

I was eighteen, traveling through Australia, and I’d heard that Coober Pedy was the opal capital of the world. I took a bus into the desert, visited a mine, and bought a beautiful black opal from a man who swore it was the real thing. It was expensive—at least for an eighteen-year-old—and I carried it home like a treasure.

Years later, I showed it to a gemologist. She took one look, held it to the light, and said, “It’s a doublet.”

I didn’t know what that meant.

She explained that a doublet is a thin slice of real opal glued onto a backing of dark potch or glass. The stone was real opal—just not solid. Just not what I’d paid for. The man in Coober Pedy hadn’t lied exactly; he’d just failed to mention that my “black opal” was a composite.

I should have been angry. Instead, I was fascinated. That stone taught me about the difference between solid and composite opal, about how fragile this gem can be, and about why opal is a stone you need knowledge to buy and care to wear.

I still have that doublet. It’s beautiful. And every time I look at it, I remember that opal is not just a stone—it’s a lesson.

This guide covers what opal is and why it flashes color, the main varieties, its place as an October birthstone, how to wear and clean it safely, realistic price ranges, and how to tell solid opal from composites and imitations. For deeper dives, see our articles on opal meaning and symbolism, the myths and legends of opal, how to clean an opal ring safely, and opal vs moissanite.

Opal at a Glance

Category	Details
Color(s):	All colors of the rainbow, often in combination; body color can be white, black, gray, crystal, or boulder
Composition:	Hydrated silica (SiO₂·nH₂O), typically about 3–10% water
Hardness (Mohs):	5.5 – 6.5 (brittle; hardness is not the same as toughness)
Structure:	Amorphous (no true crystal structure); gemologists classify opal as a mineraloid
Transparency:	Transparent to opaque
Typical treatments:	Most opal is sold untreated, but some is impregnated, smoke- or sugar-treated (especially dark matrix and some Ethiopian material), or made into doublets and triplets—always ask for disclosure
Care:	No ultrasonic or steam cleaners; avoid heat, dryness and chemicals; wipe gently with a damp cloth
Common uses:	Pendants, earrings, brooches, rings (with care), collector specimens, cabochons
Birthstone month(s):	October (modern list, alongside tourmaline); appears on some lists for the 14th wedding anniversary
Zodiac association:	Libra and Scorpio in some astrological traditions (lists vary)

What Is Opal?

Let’s begin with the most remarkable fact about opal, the one that makes it unlike most other gemstones.

Opal is not a crystal.

Most gemstones—diamond, sapphire, emerald, garnet—are crystalline. Their atoms are arranged in orderly, repeating patterns. Opal has no such long-range order. It’s amorphous, meaning its atoms are arranged randomly, like those of glass.

Chemically, opal is hydrated silica (SiO₂·nH₂O)—essentially the same ingredient as quartz, but with water trapped inside. The water content typically ranges from about 3% to 10%, and can be higher in some stones. Because it is not a true mineral with a fixed crystal structure, opal is classed as a mineraloid, and its water content is part of why it needs special care.

How Opal Forms

Opal forms when silica-rich water seeps into cracks and cavities in the earth. Over millions of years, the water evaporates, leaving behind deposits of tiny silica spheres. When those spheres are packed in a regular, orderly pattern, they create opal’s signature play-of-color.

The Science of Color

The silica spheres in precious opal are arranged in a grid-like pattern. When light enters the stone, it diffracts—bends and splits—into its component colors. It is a different mechanism from the way a prism works, but the result is a similar spectrum, produced inside the stone.

The size of the spheres influences which colors appear:

• Smaller spheres: Produce blues and violets
• Larger spheres: Produce reds and oranges

Red is the rarest play-of-color because it requires the largest, most evenly arranged spheres.

The Water Factor

Because opal contains water, it’s more delicate than many gems. It can dry out and crack (craze) if exposed to extreme heat or sudden temperature changes. It can also absorb liquids and oils, which can affect its appearance.

Where Opal Is Found

• Australia: The world’s primary source of precious opal (commonly cited as well over 90% of production). Major fields include Coober Pedy (known for white and crystal opal), Lightning Ridge (the best-known source of fine black opal), Andamooka, and Queensland (boulder opal).
• Ethiopia: Since the 1990s, Ethiopian opal has become a major force in the market. Welo opal is known for bright colors and is often hydrophane—it can absorb water and temporarily become more transparent.
• Mexico: Famous for fire opal—transparent to translucent opal with warm orange, yellow, and red body color, often without play-of-color.
• Brazil: Produces a variety of opals, including precious and common opal.
• United States: Nevada and Idaho produce precious opal.
• Honduras, Guatemala, Japan, Indonesia, Slovakia: Minor sources with historical significance.

Opal Meaning & Symbolism

Opal carries more layered and contradictory meaning than almost any other gem. It has been loved, feared, and debated for millennia. The accounts below are history, folklore and belief rather than gemology; for the full story, see our opal meaning guide.

Ancient Origins

The name “opal” is generally traced to the Sanskrit upala, meaning “precious stone”, through Greek (opallios) and Latin (opalus) before reaching English.

The Romans and the Consul’s Stone

The Romans treasured opal. Pliny the Elder described it as combining “the fire of the ruby, the brilliant purple of the amethyst, the sea-green of the emerald, and the blue of the sapphire, all glittering together in union”.

Pliny also tells of the Roman senator Nonius, who fled into exile rather than surrender his prized opal to Mark Antony, who reportedly wanted it for Cleopatra. This story, whether true or legendary, captures the stone’s power to inspire devotion.

The Arabian Myth

Arabs believed opals fell from heaven in flashes of lightning, which gave them their fire. This poetic origin story echoes the stone’s explosive play-of-color.

The Unlucky Opal Myth

In the 19th century, Sir Walter Scott’s novel Anne of Geierstein featured an opal associated with misfortune. The story was fiction, but the idea that opal is unlucky spread widely afterward and persisted for decades. Writers still debate how much the novel alone changed buying habits.

Queen Victoria and the Revival

Queen Victoria is often credited with helping to counter the superstition; she is known to have owned and given opal jewelry. Accounts differ on how decisive her influence was, but opal gradually returned to fashion.

The Aboriginal Dreamtime

Opal is culturally significant in several Aboriginal Australian traditions, and accounts differ between communities. One widely retold story tells of a creator who came to earth on a rainbow, and where his foot touched the ground, the stones began to shimmer with all the colors of the rainbow—creating opal. We share it here as one retelling, not as the account of any particular nation.

Modern Symbolism

In modern symbolism, opal is commonly associated with:

• Creativity and imagination: Its endless color play inspires artists and dreamers
• Hope and purity: Old associations with light and goodness persist
• Emotional expression: Traditionally said to help the wearer express true feelings
• Protection: For travelers, and in folk belief against negative influences
• Fidelity and faithfulness: Linked to anniversary gifts

For those born in October, opal is often tied to the colors and changes of autumn.

Opal Healing Properties: Beliefs, Not Medicine

Gemstones are not medicine, and nothing in this section is medical advice or a claim that opal treats any condition. These are beliefs from folklore and modern crystal-healing practice, not proven effects. Please see a doctor for any health concern.

Historical Beliefs

Historical sources report that people believed opal could protect against disease and, in some accounts, even make the wearer invisible. It was also thought to bring good fortune and to keep blonde hair from fading.

Modern Crystal-Healing Associations

Some modern crystal-healing practitioners associate opal with:

• Emotional balance: Said to help the wearer process and release old emotions
• Creativity: Said to inspire imagination and artistic expression
• Confidence: Said to encourage self-expression
• Calm: Its shifting colors are traditionally linked with a calm, reflective mood (a belief, not a treatment for anxiety)
• Intuition: Said to enhance intuition and dream recall

Chakra Associations

In chakra practice, opal is associated with all chakras, as it contains many colors. Different opal colors are said to correspond to different energy centers:

• Black opal: Root chakra (grounding, protection)
• Fire opal: Sacral chakra (creativity, passion)
• Crystal opal: Crown chakra (spiritual connection)
• Blue and green opal: Throat and heart chakras (communication, love)

Opal Colors & Varieties

Opal occurs in more varieties than almost any other gem. Understanding them is essential to buying with confidence.

The Body Color Categories

Precious opal is classified first by its body color—the background against which the play-of-color appears.

Variety	Body color	Best-known sources	Typical character
Black opal	Dark gray, blue, green or black	Lightning Ridge, Australia	Most valued; vivid color against a dark background
White (light) opal	White, cream, pale gray	Coober Pedy, Australia	More abundant and affordable; softer flash
Crystal opal	Transparent to semi-transparent	Australia, Ethiopia	Color seems suspended inside the stone
Boulder opal	Opal veins on brown ironstone	Queensland, Australia	Natural ironstone backing adds stability
Fire opal	Yellow, orange, red	Mexico	Valued for body color; often no play-of-color
Common opal (potch)	White, gray, green, pink, blue	Worldwide	No play-of-color; pink Peruvian “Andean opal” is used in jewelry

Black Opal

Black opal is the rarest and most valuable opal. Its dark body color makes the play-of-color appear vivid and intense. Lightning Ridge in New South Wales, Australia, is the world’s best-known source of fine black opal. The finest stones show bright, saturated colors—especially red—against a deep, even dark background.

White Opal

White or light opal has a light body color—white, cream, pale gray—with play-of-color floating across the surface. Coober Pedy in South Australia is the classic source. White opal is more abundant and affordable than black opal.

Crystal Opal

Crystal opal is transparent to semi-transparent, with play-of-color visible within the stone rather than just on the surface.

Boulder Opal

Boulder opal forms in cracks and cavities in ironstone in Queensland, Australia. The opal usually stays attached to its natural brown ironstone backing, which adds stability and creates unique, organic designs. Fine boulder opal can command high prices.

Fire Opal

Fire opal is transparent to translucent with warm body colors, often without play-of-color. Mexico is the classic source. It is valued for its intense body color rather than its flash.

Common Opal (Potch)

Common opal lacks play-of-color but can be attractive in shades of white, gray, green, pink, and blue. Pink common opal from Peru is sometimes called “Andean opal”.

The Play-of-Color Patterns

Opal collectors have names for the patterns of color:

• Pinfire: Small, distinct patches of color
• Harlequin: Large, distinct, closely set patches—the rarest and most prized pattern
• Flash: Broad flashes of color that shift as the stone moves
• Mackerel: Striped pattern
• Peacock: Predominantly blue and green, like peacock feathers
• Chinese writing: Veins of color that resemble Chinese characters

Hydrophane Opal

Some opal, notably much Ethiopian material, is hydrophane, meaning it absorbs water and can become temporarily more transparent. Wetting such a stone can change its appearance, and repeated wetting is best avoided; if it does get wet, let it dry naturally and completely.

Is Opal a Birthstone?

Yes—opal is a birthstone for October, though the exact list depends on which tradition you follow.

October Birthstone

Opal is one of two modern birthstones for October, alongside tourmaline. Opal was listed for October in the 1912 birthstone list from the American National Retail Jewelers Association, and tourmaline was added in 1952 by the same body, by then renamed Jewelers of America. Traditional and international lists differ, so some sources name other stones for October.

14th Wedding Anniversary

Opal appears on some lists as the gift for the 14th wedding anniversary; anniversary lists vary by source and country. The symbolism usually offered is a relationship that has developed depth over many years.

Zodiac Associations

In some astrological traditions (lists vary), opal is linked with Libra (September 23 – October 22) and Scorpio (October 23 – November 21). These are cultural associations, not a single agreed list.

Opal vs Tourmaline: Choosing an October Stone

If you are buying for an October birthday and want something sturdier for daily wear, tourmaline is the other modern October birthstone. Tourmaline is a crystalline mineral with a hardness of roughly 7–7.5, so it is generally better suited to everyday rings than opal, while opal offers play-of-color that tourmaline cannot. Many buyers choose an opal pendant or earrings and keep tourmaline for a ring.

Opal Uses in Jewelry

Opal’s moderate hardness (5.5–6.5) and water content require careful consideration in jewelry design. For a broader look at how hardness works, see our gemstone hardness scale guide. Hardness measures scratch resistance; opal is also brittle, so it can chip or crack on impact.

Durability Considerations

Opal can be scratched, chipped, or cracked if handled roughly. Because everyday dust contains quartz (hardness 7), even light abrasion over time can dull an opal’s surface. It can also craze (develop fine cracks) if exposed to extreme heat, sudden temperature changes, or very dry conditions.

This means:

• Rings: Suitable for occasional wear with protective settings. Opal is a risky choice for an everyday engagement ring; remove it during activities that might cause impact.
• Earrings: Excellent choice—minimal wear and tear
• Pendants and necklaces: Very safe—protected from impact
• Bracelets: Use caution—bracelets knock against surfaces
• Brooches and pins: Excellent—protected by clothing

Protective Settings

Opal should be set in a way that protects its surface:

• Bezel settings: Metal surrounds the stone, protecting the edges
• Halo settings: Surrounding stones can absorb impact
• Recessed settings: Stone sits below the metal’s highest point

Prong settings leave an opal’s edges exposed, so they are the least cautious choice, particularly for rings.

Popular Jewelry Types

Opal pendants are the safest and most popular choice. A single opal on a delicate chain catches light while staying protected. Opal earrings—studs, drops, or dangles—face minimal impact risk. Opal rings are beloved but need protective settings and thoughtful wear. Opal and diamond combinations are classic, with the white sparkle of diamonds contrasting with opal’s color play.

Metal Choices

• Yellow gold: Traditional and warm—especially flattering with fire opal and boulder opal
• White gold and platinum: Modern contrast—effective with crystal opal and black opal
• Rose gold: A romantic complement for white and crystal opal

Other Soft Stones to Compare

Opal shares its care needs with other delicate gems. See our guides to pearl, turquoise and moonstone, which also benefit from protective settings and gentle cleaning.

Opal Value & Price

Opal pricing is complex, and fine black opal can command some of the highest prices per carat of any gemstone.

What Affects Price

Body color is the most important factor. Black opal is generally the most valuable, followed by crystal, white, and boulder in many price comparisons. Play-of-color is the second: bright, intense stones are worth more than dull ones, red is the rarest and most valuable color, and harlequin is the most prized pattern. Clarity matters, especially in crystal opal, and in black opal the body color should be even and dark. Size affects price steeply, and origin matters—Lightning Ridge black opal commands the highest prices, while Ethiopian opal is more affordable but can be very attractive. Most opal is sold untreated, but some is stabilized, impregnated, smoke-treated or sold as a doublet or triplet, which should always be disclosed.

Approximate Price Ranges (USD per carat)

Opal type	Typical range	Top end
White opal	About $5–$500	Brilliant, strongly patterned stones can exceed $1,000
Crystal opal	About $30–$500 (light Coober Pedy material)	Black crystal from Lightning Ridge can exceed $3,000
Boulder opal	About $30–$3,500 across the range	Full-face, vivid stones are at the upper end
Black opal	About $500–$3,000 for commercial grade	$10,000+ for rare patterns or dominant red; exceptional stones can exceed $50,000
Ethiopian opal	About $5–$300	Varies with transparency and color

These are rough retail ballparks drawn from dealer price guides, not quotes. Prices vary widely with individual stone quality, cut and seller, and change over time. Always compare current listings and ask whether a stone is solid, a doublet or a triplet before you pay.

How to Identify Real vs Fake Opal

Opal is commonly imitated, and composites are widely sold. Understanding the differences is essential.

Solid Opal

Natural, solid opal is one piece of opal, all from nature. This is the most valuable form.

Composite Opals

• Doublet: A thin slice of precious opal glued onto a backing of dark potch, ironstone, or glass. The backing provides stability and, if dark, enhances the play-of-color. Doublets contain real opal but are not solid, and should be sold as doublets.
• Triplet: A thin slice of precious opal between a backing and a clear domed top (quartz or glass). The cap protects the soft opal and magnifies the color. Triplets are also real opal composites.

Lab-Created Opal vs Imitations

A lab-created (synthetic) opal is produced in a laboratory and has a genuine play-of-color; it is made of the same basic material as natural opal but is not natural. A simulant, by contrast, only imitates opal’s look. Lab-created opal is not fake in the sense of being glass, but it should be sold and priced as lab-created.

• Opalite: A manufactured glass that mimics opal’s appearance but lacks natural play-of-color
• Slocum stone: A glass imitation with flecks of color suspended within
• Plastic: Lightweight and soft—rare but exists

Visual Clues

• Pattern: Natural opal has irregular, organic patterns. Lab-created opal and imitations often show unusually regular patterns, though a gemological report is the only reliable test.
• Doublet/triplet edge: Look at the side of the stone. A glue line or abrupt change in material suggests a composite.

The Best Approach

Buy from reputable dealers who clearly state whether opal is solid, doublet, triplet, or lab-created, and who offer a return policy. For fine or expensive stones, ask for an independent gemological report.

Opal Buying Checklist

1. Confirm in writing whether the stone is solid, a doublet, a triplet, or lab-created.
2. Ask about treatments, including impregnation, stabilization and smoke treatment.
3. View the stone under different lighting; play-of-color can look very different in sunlight and indoors.
4. Match the stone to the jewelry: choose a protective setting for a ring, or a pendant or earrings for everyday wear.
5. Check the seller’s return policy before purchase.

Care & Cleaning of Opal

Opal requires more careful handling than most gemstones. For step-by-step help, see our guide to cleaning an opal ring and avoiding crazing.

The Water Question

Traditional wisdom: Opal contains water and can dry out, so it should be stored with a damp cloth.

Modern understanding: Many opals, especially Australian, are stable and won’t dry out under normal conditions. However, extreme heat, very dry environments, and sudden temperature changes can cause crazing.

Ethiopian opal is often hydrophane, meaning it can absorb water. Getting it wet can temporarily change its appearance.

The safe approach: Avoid getting opal wet unnecessarily. Remove opal jewelry before washing hands, showering, swimming, or doing dishes. If it does get wet, let it air dry naturally—never use heat.

Cleaning Methods

1. Use lukewarm water and a few drops of mild dish soap
2. Gently wipe with a soft, damp cloth—do not soak (doublets and triplets can come apart or fog if soaked)
3. Rinse quickly if needed, but avoid prolonged water contact
4. Pat dry immediately with a soft cloth

Never use:

• Ultrasonic cleaners: Can damage opal
• Steam cleaners: Thermal shock can crack opal
• Harsh chemicals: Can damage the stone
• Abrasive cleaners: Will scratch the surface

Storage Tips

• Store opal separately from harder stones
• Individual soft pouches or compartmentalized boxes are ideal
• Avoid extreme heat or very dry environments
• Some people store opal with a slightly damp cloth in a sealed bag to maintain humidity—but this is debated and may not be necessary for stable opals

What to Avoid

• Extreme heat and sudden temperature changes: Can cause crazing or cracks
• Prolonged direct sunlight: Best avoided during storage
• Dry environments: May cause crazing in some opals
• Hard knocks: Opal is brittle and can crack
• Perfume, hairspray, cosmetics: Can dull or stain the surface, especially in porous stones
• Chlorine and bleach: Can damage opal

Wearing Opal

Opal is best worn in situations where it is unlikely to be knocked. Put it on after cosmetics and perfume, take it off before cleaning, exercise, gardening or sleep, and store it safely.

Famous Opals

The Olympic Australis

Often described as the largest and most valuable gem opal ever found. It was discovered in 1956 at the Eight Mile field near Coober Pedy, South Australia, and weighs about 17,000 carats (roughly 3.45 kilograms).

The Aurora Australis

A famous black opal found at Lightning Ridge in 1938, weighing 180 carats and displaying a harlequin pattern in blue, green and red.

Final Thoughts

I still have that doublet—the one that taught me about opals. It sits in a simple silver pendant now, the thin slice of precious opal glowing against its dark backing, protected by a bezel setting. It’s still opal, and it still flashes red and green and blue when the light hits it right.

Opal rewards buyers who ask the right questions: is it solid, how is it set, and how will it be worn? Choose a protective setting, keep it away from heat and chemicals, and it can be worn and enjoyed for years.

Explore More Opal and Gemstone Guides

• Opal Meaning: History, Symbolism, Spiritual Properties & Modern Uses
• The Fire of Opal: Myths and Legends
• Safest Way to Clean an Opal Birthstone Ring
• Opal vs Moissanite for Fire and Shine
• Tourmaline and Pearl, Sapphire, Topaz: other gemstone guides in our library

Ready to find your own opal? Browse the collections below.

[Shop Black Opal]
[Shop White Opal]
[Shop Crystal Opal]
[Shop Boulder Opal]
[Shop Ethiopian Opal]
[Shop Fire Opal]
[Shop October Birthstone Collection]

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