A 17.05 carat Ceylon moonstone — 18.74 ratti — priced at Rs. 10,350. That is about Rs. 607 per carat, and among the large stones in this collection it is one of the better rates on offer.

The rate, in context

Across our twenty moonstones the per-carat figure runs from roughly Rs. 481 to Rs. 776. This stone sits well toward the lower end while still being one of the heaviest pieces we hold. Big stones usually cost more per carat, not less, because large clean rough is scarcer than small — so a heavy stone at a modest rate is the combination worth looking for. If you are weighing several large pieces against each other, start here.

Blue sheen

The blue is adularescence, an optical effect rather than a colour: light bouncing between alternating feldspar layers far too thin to see, scattering the shorter blue wavelengths back at you. Because it depends on angle, it rolls across the dome as the stone turns and disappears entirely when you catch it wrong. A broad dome like this one gives the effect room to move, which is the practical advantage of buying weight in moonstone.

Wearing it

At seventeen carat this is pendant territory, or a deliberately large ring for occasional wear. Moonstone is 6 to 6.5 on the Mohs scale with good cleavage, so it dislikes sharp knocks more than it dislikes scratches. Bezel settings protect the girdle; claws leave it exposed. Take the piece off before sport, housework or anything involving grit.

Care and what we have not recorded

Clean with warm water, mild soap and a soft cloth. Keep it away from ultrasonic cleaners, steam, bleach and ammonia, and store it apart from harder stones. Recorded as a Ceylon stone. Treatment has not been tested on this piece, which we state plainly rather than describing it as untreated. Dimensions and clarity are not recorded yet — ask us and we will measure it before you buy.

This particular stone

This listing is one natural moonstone with a weight of 17.05 Carat. Its price is Rs. 10,350 — roughly Rs. 607 for each carat. Origin: Ceylon (Sri Lanka). Treatment: treatment not tested. Quote reference GS-000411 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 moonstone rates 6 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 moonstone 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 moonstone 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): Moonstone is usually untreated. 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.