A small opal under a carat gives you a flicker of colour. A stone of two and a half carats gives you a pattern. This one sits firmly in the larger half of what most people consider for jewellery: big enough to carry a pendant alone, and big enough for the colour play to be read from a short distance.

What does that mean in daily life? A bigger opal catches more knocks, and at 5.5 to 6.5 on the Mohs scale it is softer than most of what sits beside it in a jewellery box. A pendant is the practical choice. Look for a setting that supports the whole outline of the stone rather than holding it at a few points.

Checking any opal

Look for hairline cracks, dull patches and any glued line at the edge. Ask whether it is solid. Keep it away from steam and ultrasonic cleaners.

This stone

A natural fire opal from Australia with play of colour, reference AG-000701. Whole opal is mostly sold as found, but darkened opal exists. We sell solid natural opal and will tell you what we know about this one. Independent lab testing is your choice.

See more in the opal collection, and read our gemstone buying guide first.

It comes Cash on Delivery: Karachi usually within 1–2 working days, other cities 2–4, and you can send it back unused within 7 days.

This particular stone

This listing is one natural australian opal with a weight of 2.5 Carat. Its price is Rs. 18,750 — roughly Rs. 7,500 for each carat. Origin: Australia. Treatment: treatment not tested. Quote reference AG-000701 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, 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. No lab report yet; independent testing welcome. 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.