Three-stone ring

The three-stone style is a centre gemstone flanked by two smaller side stones. It is a ring style, meaning the overall arrangement of stones, rather than a way of holding them. Each stone can sit in prongs or a bezel, and the style can be combined with others such as cathedral shoulders.

Three-stone rings are said to symbolize a couple's past, present and future, and some accounts add friendship, love and fidelity. Treat that as a tradition people enjoy rather than a rule, since the meaning is attached to the design, not to the stones. In GIA's list of styles, the toi et moi ring is a separate style, so do not mix the two up.

The design is also a way to add presence. Intricate settings with extra stones, such as three-stone, can make the centre stone look larger, so some buyers choose a smaller centre.

That is the main design decision, and GIA's guide sets out two approaches. Side stones that match the centre in gem type and cut style create a cohesive look and add visual width. Side stones of a different shape or colour can complement or contrast with the centre.

For shape pairings, a pear shape works well in a three-stone setting, and three-stone is among the styles that suit a heart shape. Round side stones beside a round centre are the matched option. Other pairings, such as an oval centre with pear or round sides, are worth testing by looking at both.

Because the side stones are smaller, the centre stays the leader. Choose side stones in proportion: too large and they compete with the centre, too small and they look like an afterthought. Look at the ring from above and from the side.

GIA's guidance is that in an all-diamond three-stone ring, the colour grades of the side stones should typically be within about two colour grades of the centre stone. A closer match helps the three stones read as one set.

This refers to the diamond colour grade scale. It does not mean the side stones must be identical. Ask for the colour grade of each stone and compare them side by side in good light.

If you are mixing a diamond centre with a coloured gemstone, the two-grade guide does not apply, and the colour pairing becomes a matter of taste.

Total carat weight, often shortened to TCW, is the combined weight of all the stones in the ring. A metric carat is 200 milligrams, divided into 100 points. A ring described as 1.50 ct TCW might hold, for example, a centre stone of 1.00 ct and two side stones of 0.25 ct each.

That figure alone does not tell you how big the centre looks. Ask for the weight of the centre stone and of each side stone separately, and check which stones come with a grading report. The centre leads the design, and the side stones add width.

Cost follows the number of stones. Intricate settings with additional smaller stones, such as three-stone, raise the price because of the extra stones and labour. They can also make the centre stone look larger, which may let a buyer choose a smaller centre. Compare the complete ring, not only the total weight.

Start with the centre stone and its shape, then choose the side stones, then the metal and the way each stone is held. Because the ring is wider across the front, check that it is comfortable beside the neighbouring finger and with your wedding band.

To start a design brief, use the design studio. A custom engagement ring starts from the shape and setting you describe. Finished three-stone designs can be viewed through the engagement ring collection or at a showroom.