Ornella Engagement Ring in 18K White Gold

Platinum is naturally white and the densest of the metals we work in, so it holds a stone securely and keeps its colour without replating. 18ct gold is an alloy — the yellow, white or rose tone comes from what the gold is mixed with.

White gold is finished with rhodium, which softens over years of wear and can be re-plated as part of a service. Every metal here is hallmarked and set by the same workshop.

Sizes are UK letters. Fingers change through the day and with the weather, so measure in the afternoon at room temperature — a ring should pass the knuckle with a little resistance and sit without spinning.

If you are between sizes, or buying as a surprise, choose the larger one. Most designs can be adjusted after purchase; wide bands and full eternity settings are the exceptions, so ask us first.

Round claws hold the stone with a smooth, rounded bead. Eagle claws finish in a fine point that holds the stone with less metal on show.

Natural Diamond
Formed deep within the Earth over billions of years under intense heat and pressure. Each natural diamond is a rare creation of nature, mined from the Earth and individually graded and certified.

Lab-Grown Diamond
Created in a controlled laboratory environment using advanced technology that recreates the conditions in which natural diamonds form. Lab-grown diamonds have the same chemical, physical and optical properties as natural diamonds, but are grown within weeks rather than billions of years.

Shape is the outline of the stone. Round brilliants are cut to return the most light, which is why they are the most common — and the most expensive per carat. Step cuts such as Emerald and Asscher trade that for broad, clear flashes, and show colour and clarity more openly.

Elongated shapes — oval, pear, marquise — cover more of the finger for the same weight. Only the shapes this setting is made for are shown.

Coloured stones are cut to make the most of the colour in the rough, so the shape you find depends on what the material allowed. Ovals and cushions are the most widely available; rounds in larger sizes are harder to source.

Because of that, treat shape as a preference rather than a filter to hold firmly — widening it usually opens up better colour at the same budget.

Ruby and sapphire are the same mineral, corundum, and are second only to diamond for hardness — both wear well in a ring worn daily. Emerald is softer and more often included, so it suits a protective setting.

Colour, not species, drives most of the price: a vivid stone of a common type can cost more than a pale example of a rare one.

Carat is weight, not size — one carat is 0.2 grams. Two stones of the same weight can look quite different across the top depending on how they are cut, and how deep the stone sits below the setting.

Prices step up sharply at the round numbers, so half a point under a full carat often buys a visibly similar stone for noticeably less.

Diamonds are graded on a colour scale from D to Z, with colourless stones considered the rarest and most valuable. While many diamonds contain subtle traces of yellow, these are often invisible to the naked eye.

As you move further down the scale, warmer tones become more noticeable, offering a wider range of characteristics and price points.

Clarity describes the inclusions formed while the diamond grew. It runs from FL, where none are visible under ten-times magnification, through VVS and VS to SI, where they can be found more easily under a loupe.

From VS upward a stone is almost always clean to the naked eye. At SI it depends on where the inclusion sits, so we check each one and can tell you what to expect before you commit.

Nearly every coloured stone sold today has been treated to bring out its colour or clarity, and the trade has accepted that for centuries. Heat is the most common and the most stable — it does permanently what time in the ground would have done slowly.

Oiling fills the fine fissures that emeralds almost always carry, and is expected in an emerald rather than hidden. Untreated stones of good colour are genuinely rare, and priced accordingly. Whatever a stone has had done to it is stated on its certificate and on its page here.

A gemstone report names the species, states where the colour came from, and records any treatment. Unlike diamonds there is no single grading scale behind it, so the lab's own judgement carries more weight.

GIA and GSI certify the largest share of what we can source. GRS, AGL and AGTL specialise in coloured stones and are the names to look for on a significant ruby, sapphire or emerald.

Set the least and the most you would like to spend, and we search for stones priced between the two. Choose £50,000+ as your maximum to leave the top end open.

The three recommendations sit inside your range, except the last, which may reach up to ten per cent above your maximum where a stone is worth stretching to.