A 10.60 carat blue topaz is a big stone, and the smart way to buy one is to know exactly what to check. Here are the points that matter for this piece.

• Weight: 10.60 carats, a generous size for a ring or pendant.
• Hardness: 8 on the Mohs scale, good for rings, but protect the edges from hard knocks.
• Colour: produced by irradiation and heating, standard for topaz and stable in normal wear.
• On arrival: look at it in daylight and then under a lamp to see how the blue behaves.
• Surface: check the girdle and facets for chips, since topaz is brittle along one direction.
• Questions: message us on WhatsApp quoting AG-BL-0006.

If you are weighing it against other sizes, the whole blue topaz page lists them side by side.

Cash on Delivery means the parcel is opened and the stone inspected before you pay anything. Karachi orders usually arrive within 1 to 2 working days and the rest of Pakistan within 2 to 4, and you can return the stone unused within 7 days if it is not what you expected. Before you choose, read our blue topaz guide.

This particular stone

This listing is one natural blue topaz with a weight of 10.6 Carat. Its price is Rs. 9,600 — roughly Rs. 906 for each carat. Treatment: treatment not tested. Quote reference AG-BL-0006 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.

From six carats up a stone becomes the centre of attention. It wants a broader shank or a secure claw setting and suits an occasion ring, a signet or a centre pendant. Clean natural material of this size turns up far less often, and the per-carat rate reflects that.

On the Mohs scale blue topaz rates 8. Few materials will scratch it, so it copes well with everyday ring wear. A soak in warm water with a drop of mild soap and a soft brush keeps it bright; skip the ultrasonic cleaner if inclusions reach the surface.

Whoever you buy blue topaz 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 blue topaz 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): Blue topaz gets its blue colour from irradiation and heating — this is standard for the stone and the colour is stable. 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.