Opal Meaning: The Rainbow Stone That Holds Water

Opal meaning starts with a surprise: opal has water locked inside it. It's a mineral that never quite dried out, and the best pieces flash every colour of the rainbow when you tilt them. Here's what it is, what it's traditionally linked with and how to look after it.

What opal actually is

Opal is hydrated silica. That means it's made of the same basic stuff as quartz, plus water held in its structure. Unlike quartz, it has no crystal shape. It forms when silica-rich water seeps into cracks and hollows in rock, then slowly hardens.

There are two big groups. Precious opal shows "play of colour", those shifting flashes of red, green and blue. Common opal doesn't. It can still be lovely, in milky white, pink, orange or honey tones, just without the rainbow.

The rainbow comes from tiny spheres of silica stacked in neat rows. When they're all the same size, they split light into colours, a bit like the back of a CD. GIA's opal guide has more on how it forms.

Opal rates about 5.5 to 6.5 on the Mohs hardness scale. That's softer than quartz, so it can scratch or chip with rough wear.

Opal meaning: what it's traditionally linked with

Opal is traditionally linked with creativity, self-expression and hope. All that colour shifting made it a symbol of change and imagination. People who make things, from painters to bakers, often say it's their stone.

Opal is the October birthstone, shared with tourmaline. Our October birthstone guide covers both. In modern chakra charts it's often placed with the crown, and zodiac lists usually pair it with Libra.

It even had a bad patch. The story goes that a popular 19th-century novel made readers think opal was unlucky, and the rumour stuck around for decades. Today it's back to being one of the most loved gems.

How people use opal

• As a specimen. The cherry opal mineral is a warm red-orange common opal for a shelf or collection.
• As tumbled stones. Dendritic opal tumbled stones are pale opal with dark, fern-like markings from other minerals. They make good pocket stones.
• On the wrist. The opal bead bracelet is an easy way to wear it every day, with a bit of care.
• In jewellery. The collection also has opal stud earrings and necklaces, plus a few look-alikes, which we explain below.

See the whole shelf in the opal collection.

Who tends to choose it? People born in October, of course. Also anyone who loves colour and can't pick just one. Opal is a popular gift for a milestone birthday or an anniversary, and creative types often adopt it as a mascot.

Why opal is precious

Precious opal is valued for its play of colour. The more colours, the brighter they are and the bigger the patches, the more it's worth. Red flashes are the rarest, so they push the value up. A dark background makes the colours pop, which is why black opal is so prized.

Most of the world's precious opal comes from Australia. Boulder opal is one Australian type, where thin veins of opal form inside ironstone. Cutters leave the brown rock on the back, so you get a rainbow on a natural backing. Fire opal is another favourite. It's a see-through orange to red opal, and it may or may not have play of colour.

Is my opal real? Doublets, triplets and look-alikes

Opal is easy to imitate, so it pays to know the names.

• Doublet: a thin slice of real opal glued onto a dark backing to boost the colour.
• Triplet: a doublet with a clear dome of quartz or glass on top to protect it.
• Opalite: this is glass, not opal. It glows blue against dark and peach against light. We label it "(Synthetic)" in the title. Our opalite meaning guide tells the whole story.
• Opal aura: quartz with a thin shimmery coating. It's pretty, but it isn't opal either.

A doublet or triplet often has a flat, perfectly even look from the side, with a visible seam. Lab-grown opal exists too, and its colour patches can look very regular, almost like snakeskin. Treated, dyed and man-made stones are labelled as such in our shop, so you'll always know which one you're holding.

Caring for opal

Opal holds water, so it doesn't love extremes. Keep it away from strong heat and sudden temperature changes, like a hot car dashboard or going straight from the cold into hot water. In very dry conditions some opal can dry out and develop fine cracks, called crazing.

Clean it with a soft cloth and lukewarm water. Never soak doublets or triplets, because water can loosen the glue. Skip harsh cleaners and ultrasonic machines. Store it on its own so harder stones don't scratch it, and take rings off before the gym or the garden.

Stones that pair well with opal

Opal's soft rainbow sits well beside other stones that play with light. Tiger eye has a moving golden shine, and fluorite mixes purple, green and blue in one stone. For a calm blue partner, try turquoise. For a deep contrast, black onyx makes the colours pop.

More stone guides to explore: agate, obsidian, malachite, peridot and pyrite. Our stone meanings page has the full shelf, and the skeptic's guide to crystals is there if you're still deciding what you believe.

Not sure opal is your stone? The Crystal Quiz takes a couple of minutes and points you somewhere.

Frequently asked questions

Why is opal precious?

Precious opal shows play of colour: rainbow flashes made by tiny silica spheres splitting light. Bright, large patches of colour, especially red, make it more valuable.

What are doublet and triplet opals?

A doublet is a thin slice of real opal glued to a backing. A triplet adds a clear cap of quartz or glass on top. Both are real opal, just assembled, and they shouldn't be soaked.

Who should not wear an opal stone?

There's no rule. The practical caution is that opal is fairly soft and holds water, so it's not ideal for rough work. Keep it away from heat, knocks and harsh cleaners.

Is opal a good name for a girl?

Plenty of people think so. It's a gem name like Ruby or Pearl, and it suits an October baby nicely.

Is opalite the same as opal?

No. Opalite is man-made glass with a blue and peach glow. Opal is a natural mineral that holds water.

What is boulder opal?

It's opal that forms in thin veins inside ironstone. It's cut with the brown rock left on the back as a natural backing.

Come say hi

Opal's colours change with every tilt, so it's best seen in your own hand. Visit us at 396 Victoria Street North in Kitchener, or browse opal online.