18K Gold Sapphire Ring - 2.2ct Cabochon & Diamond Halo - UK N1/2

Sapphire Cabochon Ring – Domed Blue in a Diamond Halo, 18K Gold

The stone here is not faceted. It is a cabochon — cut as a smooth polished dome rather than into flat planes — and that changes everything about how it reads. Faceted stones chop light into sparkle; a cabochon holds it, so this oval of roughly 9.8 x 6.6mm glows with an even, liquid blue instead of flashing. It is bezel-set, a continuous rim of gold wrapped all the way round it, which both protects the dome and frames the colour without a single claw interrupting the outline.

Around that bezel runs a halo of 30 round diamonds, 1.5mm each, which then breaks and continues down a split shank — the band divides into two strands that sweep past each other before rejoining. That split is what gives the ring its movement: from above it reads as a swirl rather than a circle. Set in solid 18K gold hallmarked 750, it weighs 6.06 grams on our scales. It is a UK N1/2 (US 7, EU 54), and there is one.

FAQs

1. Does this ring come with a gemstone certificate?
No. This piece is sold uncertificated, and we would rather say so plainly than imply otherwise. The gold is hallmarked 750 and that mark is independently struck; the stone measurements, carat estimates and ring weight are our own, taken in-house. That is entirely normal for individually sourced fine jewellery, where the cost of laboratory certification often exceeds what it adds. If you would like independent verification, any gemmologist or reputable jeweller can examine and certify the stone after purchase — and our returns policy gives you time to do exactly that.

2. What is a cabochon, and why cut a sapphire that way?
A cabochon is polished into a smooth dome rather than cut with facets. It is the oldest way of finishing a gem — every stone was a cabochon before faceting was invented in the fifteenth century. Cutters still choose it when a stone's colour is its best feature, because a dome pools and holds light where facets would break it into sparkle. It is also the only cut that can show a star or cat's-eye effect, where a stone has the internal structure for it. More on gemstone cuts and meaning is on our JewelMotif™ page.

3. Are sapphire and ruby the same stone?
Yes — both are corundum. Red corundum is called ruby; every other colour, including this blue, is sapphire. Blue comes from traces of iron and titanium, red from chromium. That shared identity puts sapphire at 9 on the Mohs hardness scale, second only to diamond, and makes it one of very few coloured stones genuinely suited to everyday wear.

4. What is a split shank?
The band divides into two separate strands as it approaches the setting, then rejoins at the back. It does two things: it frames the centre stone with negative space so the stone reads larger, and it gives the ring visual movement from above. It is also more work than a plain shank, since the split has to be balanced on both sides to sit straight on the finger.

5. What does the 750 hallmark mean?
750 parts pure gold per 1,000 — 18 karat, or 75% gold, the fine jewellery standard. (585 is 14k; 375 is 9k.) Unlike a gemstone estimate, a hallmark is an independently struck guarantee of metal purity, which is why we quote it precisely. Solid gold does not tarnish and will not mark skin. Full detail is in what a UK gold hallmark really means.

6. What is UK N1/2, and will it fit me?
N1/2 is the half size between N and O — US 7, EU 54, with a 17.2mm internal diameter and a 54mm circumference. Measure against those figures rather than guessing. Our UK ring size guide has a printable method and a full UK-to-US chart. A split shank is difficult to resize without distorting the symmetry, so buy on the measurement.

7. What occasion suits it?
Sapphire is September's birthstone and the traditional 45th-anniversary gift, with centuries of association with wisdom, truth and constancy — long the choice for anyone wanting an engagement ring other than a diamond. The halo and split shank give it real occasion presence. Every order arrives gift-ready — see JewelGift™, and JewelWhy™ for the cultural history behind the stones we use.

How to Style the Sapphire Cabochon Halo Ring

The split shank already fills the finger, so wear it alone rather than stacked — a band pressed against it will rub the pave over time. Keep to yellow gold elsewhere and let the blue be the only colour on the hand. It reads formal against navy and black, and unexpectedly fresh against white and cream. Explore the rest of the 14k & 18k Gold collection, or visit JewelBuild™ to see how one significant piece anchors a modular jewellery system.