With most gems people ask for a certificate to rule out glass or synthetics. With opal there is a more specific question, and it is the one that costs buyers real money: is this one solid piece of opal, or a thin slice glued onto something else? That is what a report on an opal is most useful for.

The stone

2.15 carats, which is 2.36 ratti. Shape: oval cabochon. Origin: Australia. Rs. 10,750, about Rs. 5,000 per carat, reference GS-000727.

What certification covers on an opal

• Solid, doublet or triplet. The most valuable line. A doublet is opal glued to a dark backing; a triplet adds a clear cap. Both look convincing face-up and are worth a fraction of a solid stone.
• Natural or synthetic. Laboratory-grown opal exists and is convincing to the eye; under magnification it shows a regular columnar structure natural opal does not have.
• Treatment. Whether smoke or sugar treatment has been used to darken the body tone. Our own sheet reads "treatment not tested", so a report is the way to a definite answer.
• Weight and measurements. Independently taken, useful if you intend to insure the finished piece.

What no certificate does is grade the beauty. No laboratory will tell you whether this play-of-colour is worth Rs. 5,000 a carat — with opal more than any other gem, that is a judgement you make with your own eyes.

Getting a report on this stone

Two routes. Ask us on WhatsApp at +92 308 887 3888 and we will send it to an independent laboratory before dispatch and forward the report — we will tell you the delay first. Or take it to a laboratory of your own choosing after delivery: you pay the rider only once the parcel is open, and the seven-day return window runs from delivery, so the stone goes back unused if the result is not what you expected. Our lab-certified opal page explains the process, and the authenticity page covers how we inspect stones before listing.

Our own certificate of authenticity is available on request. It is our statement rather than a third party's, and we say so plainly.

The check you can do yourself

Look at the stone edge-on, from the side. A solid opal shows natural variation through its depth; a doublet or triplet shows a straight, flat line where the layers are joined. It takes two seconds and it is the single most useful thing you can learn about buying opal. More in our real versus fake opal guide.

Care

Opal is 5.5 to 6.5 on the Mohs scale and contains water. Soft damp cloth only — never ultrasonic or steam. Keep it out of prolonged direct sun and very dry heat, which can craze the surface. A bezel setting protects the edge better than claws.

Ordering

One piece only. Flat Rs. 500 delivery anywhere in Pakistan, insured and tracked, dispatched in one to two working days. Cash on Delivery, seven days to return it unused. Measurements have not been recorded; we will measure it on request. More in the Australian opal collection.

This particular stone

This listing is one natural australian opal with a weight of 2.15 Carat. Its price is Rs. 10,750 — roughly Rs. 5,000 for each carat. Origin: Australia. Treatment: treatment not tested. Quote reference GS-000727 when you message us about it. The photographs show this exact stone, so what arrives at your door is the piece you chose on screen.

Between two and six carats is the range most people choose for a gents' ring or a noticeable pendant. Here colour drives the price more than size does, which is why two stones of near-identical weight can be priced very differently.

Whoever you buy australian opal from, make sure of three things: the stone is natural rather than lab-grown, glass or glass-filled; any treatment is stated in writing; and the weight quoted is the weight of the finished stone. We check every australian opal for those three points before it is listed, a certificate is available on request, and because you pay on delivery you can look at the stone — or have it tested — before any money changes hands.

We sell natural stones only and inspect each one before it is listed. Treatment for this stone: Treatment not tested. Certificate available on request. As general background (not a statement about this stone): Solid opal is usually untreated; some opal is smoke- or sugar-treated, and doublets/triplets exist — we sell solid natural opal. Ask us on WhatsApp and we will tell you what we know about this exact stone; independent lab testing is available on request.

A certificate of authenticity is available on request for this stone, and independent laboratory testing can be arranged. Because you pay on delivery, you can also take the stone to a lab of your choice within the 7-day return window. Read more on our authenticity page.