Seen from across a room, a 3.75 carat opal still registers. This is a large stone by any measure and the biggest in this group. Most opals sold for everyday jewellery are between one and two carats, so a piece of this weight gives a pendant real presence.

Size brings cost. Per carat, it sits well above our smaller opals, which is normal across gemstones: bigger pieces are harder to find and are priced accordingly, even when quality is similar. The reference is AG-000602.

What to check in a large opal

A bigger surface shows more colour play, but it also leaves more room for cracks. Look for hairlines, cloudy patches and any line along the edge that could mean a doublet or triplet. With a hardness of 5.5 to 6.5 and more surface to knock, it suits a pendant or a well-protected bezel ring better than an open setting.

This is a natural fire opal with visible play of colour. Whole opal is usually left natural, though darkened stones exist in the trade. We sell solid natural opal and will tell you what we know about this one when you message us. Independent lab testing is your decision.

Smaller stones are in the opal collection, and the opal guide has more.

A stone of this size deserves a careful look in daylight, and Cash on Delivery gives you exactly that before you pay. Karachi usually 1–2 working days, other cities 2–4, returns within 7 days.

This particular stone

This listing is one natural opal with a weight of 3.75 Carat. Its price is Rs. 28,500 — roughly Rs. 7,600 for each carat. Treatment: treatment not tested. Quote reference AG-000602 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.

On the Mohs scale opal rates 5.5 to 6.5. That is middle-of-the-road hardness: comfortable in pendants and earrings, and in rings worn with some care. Store it apart from harder stones so it does not pick up scratches, and wipe it with a damp cloth rather than scrubbing.

Whoever you buy 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 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.