Real or Fake Opal? How to Check Before You Buy in Pakistan

Opal is one of the easiest stones to imitate and one of the hardest to judge from a photograph. Its whole appeal is the flash of colour that moves across the surface, and glass, plastic and lab-grown opal can all produce a flash of some kind. In Pakistani markets the problem is rarely an outright lie; more often a doublet is called "opal", a synthetic is called "Australian", or a dyed Ethiopian stone is sold as natural black opal.

This guide covers asli opal ki pehchan step by step: what each imitation is, which checks you can do at home with a torch and a loupe, which questions only a laboratory can answer, and how to buy so that a mistake costs you nothing.

What a genuine opal is

Precious opal is hydrated silica: tiny spheres of silica packed in ordered rows, with water held between them. When light passes through those rows it splits into spectral colours, and the colour changes as you tilt the stone. The trade calls this play-of-colour. Common opal has the same chemistry without the ordered spheres, so it shows a milky body but no moving colour.

Two main sources supply most opal sold in Pakistan. Australian opal, often from sedimentary deposits, includes the famous black and boulder opals. Ethiopian opal, mostly from volcanic deposits in Wollo, is typically white or crystal with bright colour and is often hydrophane, meaning it absorbs water. Opal is also October's birthstone (see our October birthstone page), and our guides to Australian opal and Ethiopian opal checks go deeper on each.

The imitations you are most likely to meet

Opalite and other glass

Opalite is a man-made glass that glows bluish against a dark background and orange against a light one. It is sold openly as a crystal-healing stone and sometimes, less honestly, as "moon opal" or plain opal. It never shows true play-of-colour: the glow is a soft, even sheen with no separate patches of spectral colour. Look closely and you may also see round gas bubbles.

Plastic and resin imitations

Some imitations embed foil or iridescent flakes in resin. They are very light, feel warm at once, and the colour sits in flat, glittery fragments rather than in patches that roll across the stone as you turn it.

Synthetic (lab-grown) opal

Laboratory-grown opal, often called Gilson or Kyocera opal after the makers who developed it, is made of real silica spheres and can show strong play-of-colour. Its tell is pattern. Under a loupe, synthetic opal often shows a regular, columnar structure from the side and a "snakeskin" or "chicken-wire" mosaic from the top, as if the colour sits in neat scales. Natural opal patterns are irregular: broad flashes, pinfire dots, rolling bands. Synthetic opal can also be impregnated with resin, which lowers its density.

Doublets and triplets

A doublet is a thin slice of real opal glued to a dark backing, often black glass, ironstone or plastic, to make the colour look stronger. A triplet adds a clear dome of quartz or glass on top to protect the thin slice. Both contain natural opal and are legitimate products when sold as such. They are worth far less than a solid stone and must never be soaked, because water gets into the glue line.

Dyed and smoked opal

Ethiopian hydrophane opal absorbs liquids easily, which makes it simple to darken. Smoke treatment and dyeing turn a white stone dark so it resembles valuable black opal. Sugar-acid treatment does the same with porous matrix opal, depositing carbon in the pores. These stones are natural opal, but the dark body colour is not, and that must be disclosed.

Home checks that actually help

None of these replaces a lab, but together they will catch most imitations before you pay.

1. Look at the stone side-on. Hold it at eye level with a torch behind you. A straight, flat line where two layers meet means a doublet or triplet. A clear dome over a thin coloured layer means a triplet. A solid opal shows the same material from top to bottom, even if the colour fades towards the base.
2. Turn it slowly under one light. True play-of-colour appears in distinct patches that switch on and off and change colour as the angle changes. Opalite glows evenly. Foil imitations glitter in the same spot at every angle.
3. Use a 10x loupe on the pattern. Natural opal patterns are random. A regular scaly or honeycomb mosaic across the whole face points towards synthetic opal.
4. Check the back. Many doublets have a black, perfectly flat, glossy back. Natural black opal is dark throughout, and boulder opal shows brown ironstone that looks like rock, not paint.
5. Feel temperature and weight. Plastic warms almost immediately and feels too light. This does not separate glass from opal, but it removes resin imitations.
6. Look for bubbles. Perfectly round gas bubbles in the body suggest glass.

Checks to avoid

Some popular "tests" damage opal or prove nothing.

• Soaking in water. Ethiopian hydrophane opal turns clear or loses its colour while wet; it usually recovers as it dries, but dyed stones may bleed and doublets may separate. Do not soak a stone you have not bought.
• The hot needle or flame test. Heat can crack opal, which holds water inside it. Never apply heat.
• Scratch tests. Opal is only 5.5 to 6.5 on the Mohs scale, so scratching it proves nothing except that you have damaged it.
• "Real opal glows under UV." Some natural opal fluoresces and some does not, and many imitations do. UV alone tells you very little.

What only a lab can confirm

A home check can show that a stone is assembled or obviously glass. It cannot reliably tell you three things:

• Whether a solid stone with good play-of-colour is natural or synthetic, when the pattern is not textbook.
• Whether a dark Ethiopian opal has been smoked or dyed.
• Whether a stone has been impregnated with resin or polymer to stabilise it.

A gem lab uses magnification, specific gravity, infrared spectroscopy and other instruments to answer these. For a higher-value opal it is worth the cost. A certificate is available on request for our stones, and independent lab testing can be arranged; see our lab-certified opal page and the guide on how to read a lab certificate, so you know what words like "assembled" or "impregnated" mean on a report.

Treatments that are acceptable when disclosed

Not every treated opal is a fake. A stabilised opal, a doublet sold as a doublet, or a smoked Ethiopian opal sold as smoked are all honest products at a fair price for what they are. The problem only arises when the treatment is hidden and the price is that of a solid, untreated stone. Ask the seller to write one of these on the invoice: solid natural opal, natural opal doublet, natural opal triplet, or synthetic opal, plus any known treatment.

If you already own an opal and have doubts

Many families have an old opal ring bought on a trip or from a travelling seller. Before assuming the worst, start with the side view: remove nothing from the setting, but look along the edge of the stone with a torch. A visible glue line or a dark layer under a thin coloured one tells you it is assembled, which is still a genuine opal product. If the stone looks solid and the pattern is irregular, the odds favour natural opal. If the pattern is a neat mosaic, or the stone is a very large, very bright black opal that cost little, a lab report is the only way to settle it. Do not have the stone removed, soaked or polished until you know what it is, because a doublet can lift and a hydrophane stone can stain.

Opal names you may hear in Pakistani shops

Sellers use loose names, and a few deserve care. "Fire opal" can mean orange Mexican opal, which is genuine, or simply any opal with strong colour. "Australian opal" is sometimes used for any good-looking opal regardless of origin. "Moon opal", "sea opal" and "galaxy opal" are usually trade names for glass or synthetics. If a name is unfamiliar, ask what mineral it is. Our Urdu and English gem names list helps with the common ones.

Price as a warning sign

A large, bright, solid black opal at a low price should make you stop. Fine black opal is one of the costliest coloured stones per carat. Ethiopian white opal is far more affordable, which is why it is common in Pakistani markets; that is no reason to doubt it, only a reason to make sure the stone is described accurately. Our planned opal price guide explains how type and pattern affect cost.

Buying opal safely

• Ask for side and back photos, not only the face. Assembled stones are easiest to spot from the side.
• Ask for a short video under a single light. Play-of-colour has to move to be judged.
• Get the description in writing: solid or assembled, natural or synthetic, origin if known, treatment if any.
• Check the weight is for the loose stone, not the stone with its backing or setting.
• Choose a seller who lets you inspect before paying.

We photograph every opal on its own and describe it as we find it. Every order across Pakistan can be paid by Cash on Delivery: open the parcel, inspect the stone and pay the rider only if you are happy. Returns are accepted within 7 days. Browse our opal collection; for example, the 1.50 carat Ethiopian opal and the 1.90 carat Ethiopian opal both show their play-of-colour in the listing photos. Our article on wearing opal and caring for it covers what to do once you own one, and the broader real or fake gemstones guide applies the same thinking to other stones.

Shop the stones: opal.