Hardness first: this 4.05 carat sapphire scores 9 on the Mohs scale, which puts it just below diamond. In practical terms, a ring set with it will survive years of sand, keys and worktops without dulling, which is far more than can be said for softer gems such as opal or pearl.

That does not make it indestructible. A hard blow can still chip a sapphire, so choose a setting that guards the edge if the ring will see heavy use, and remove it for manual work. A pendant, naturally, takes much less punishment.

The stone itself is a natural neelam, blue in colour, weighing 4.05 carats and priced at Rs. 14,250, which is about Rs. 3,519 per carat. Sapphire is commonly heated to improve its colour, and we will tell you what we know about this one when you ask. Reference GS-000839.

To clean it, use lukewarm water, a little mild soap and a soft brush; ultrasonic cleaners are generally fine for sapphire but check with a jeweller first if the stone is fracture-filled or has cracks. Store it in a soft pouch. More guidance is in our care guide, and similar stones are in the sapphire category.

Pay Cash on Delivery once you have opened the parcel and seen the stone yourself, anywhere in Pakistan, with 7 days to return it if you change your mind.

This particular stone

This listing is one natural sapphire, known in Urdu as Neelam, with a weight of 4.05 Carat. Its price is Rs. 14,250 — roughly Rs. 3,519 for each carat. Treatment: treatment not tested. Quote reference GS-000839 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 sapphire rates 9. 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 sapphire 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 sapphire 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): Most sapphire on the market is heated to improve colour and clarity; unheated stones exist and cost more. 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.