A natural topaz of 12.60 carats, about 13.85 ratti, at Rs. 25,200 – Rs. 2,000 per carat, the lowest rate in this category. Its colour is recorded as blue.

Size and colour together

Twelve and a half carats is a large stone, and this one is strongly coloured with it: about 93% of its face reads as blue and 54% as a strong, saturated blue, with only about 4% near-colourless. Several stones in this category are large but pale, or vivid but small. This one is both large and blue.

Its outline is a squared-off oval, about 1.37 times as long as it is wide, filling almost exactly the 78.5% of its bounding box that a true ellipse fills – but it occupies rather more of the corners than an ellipse would, which is why the oval name in our list went to a different stone.

At this size, the setting is the decision

Topaz is 8 on the Mohs scale, which is hard. But it has perfect basal cleavage: one plane across the crystal along which a sharp knock splits it cleanly, however hard it is. A large stone presents a bigger target and sits higher, so it is struck more often.

A pendant is the safe answer. If it must be a ring, insist on a bezel and take it off for anything rough. Tell the jeweller to set it last and keep torch heat away, and never let it near an ultrasonic cleaner or steam.

Where the blue comes from

Almost all blue topaz is irradiated and then heated. Natural blue topaz is rare and faint; the blues on the market begin as colourless topaz, are irradiated to produce the colour and heated to stabilise it. It is permanent, standard, and the reason a stone this size costs what it does rather than many times more.

For this stone the treatment has not been tested and there is no laboratory report.

Ordering

One stone, sold once. Message us on WhatsApp for more photographs or a video, and we deliver across Pakistan.

This particular stone

This listing is one natural topaz, known in Urdu as Sunehla, with a weight of 12.6 Carat. Its price is Rs. 25,200 — roughly Rs. 2,000 for each carat. Treatment: treatment not tested. Quote reference GS-000483 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.

Above twelve carats you are into collector territory. Pieces this heavy are usually set as pendants or kept loose, and they are prized for the size of rough they came from. If you do set it, choose a bezel or a heavy claw to protect the edges.

On the Mohs scale 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 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 topaz 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): Yellow and golden topaz is usually untreated, though some colours are produced by heating. 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.