Best Settings and Metals for Coloured Diamonds: A Gemmologist's Guide

What makes coloured diamonds coloured?

A pure diamond is carbon in a tight, regular crystal lattice, and it has no colour at all. Coloured diamonds get their hue from something extra: a trace element sitting where a carbon atom should be, a distortion in the crystal, or damage from natural radiation deep underground. The trade calls any diamond with colour beyond the normal white-to-faint-yellow range a fancy colour diamond. Our full guide to fancy colour diamonds covers every hue in depth; this page focuses on what each colour means for the setting and metal you choose.

The cause of the colour also hints at how the stone behaves in a ring. Blue Type IIb diamonds are very pure apart from the boron and are usually clean. Black diamonds are coloured by dense inclusions, which makes them more brittle than other diamonds. Pinks often show colour graining: fine parallel lines left by the same deformation that turned them pink.

All coloured diamonds are still diamond: 10 on the Mohs hardness scale, with a refractive index of about 2.42. The difference is that colour, not sparkle, drives their value, so cutters often choose shapes such as the radiant and cushion, which hold and concentrate colour, over a round brilliant that is cut to maximise brightness.

How are coloured diamond intensity grades worked out?

White diamonds are graded on the D-to-Z scale, where less colour is better. Fancy colour diamonds flip that logic: more colour is usually worth more. GIA describes a coloured diamond by three things: hue (the colour itself, such as pink), tone (how light or dark it is) and saturation (how strong or pure the colour is). Together these give one of nine intensity grades, judged face-up against a neutral background in controlled light. If any of these words are new, our plain-English jewellery glossary defines them.

Most hues also carry a modifier. In Fancy Intense Purplish Pink, pink is the main hue and purplish is the secondary hue; the last word always names the dominant colour. Some modifiers are popular (purplish pink) and some lower the price (brownish pink usually costs less than pure pink). For yellow and brown diamonds, the Faint to Light grades fall inside the ordinary D-to-Z range, so a yellow is only called fancy once its colour is stronger than the Z master stone.

Why this matters for the setting: the lighter the grade, the more the metal around the stone changes what you see. A Fancy Vivid yellow holds its colour in any metal. A Fancy Light yellow or a Light pink can look noticeably weaker in white metal, or a little stronger in yellow or rose gold.

Natural, lab-grown or treated: how can you tell the difference?

A coloured diamond can reach you by three routes, and they look alike to the eye. The grading report is how you know which one you are looking at.

Every GIA Colored Diamond Grading Report has a line called colour origin. It is the most important line on the page, because it tells you whether the colour you are paying for formed in the ground. Three examples of what a GIA colour origin report can show:

• Fancy Intense Yellow, colour origin Natural: the colour formed in the earth. This is the result you expect for a natural yellow priced as one.
• Fancy Deep Blue, colour origin Treated: a natural diamond whose colour was produced or changed after mining, for example by irradiation. It is still natural diamond, but priced well below a natural-colour blue.
• Colour origin Undetermined: the lab could not reach a firm conclusion, which happens most often with green diamonds. Ask about further testing, or price the stone as though it may be treated.

Lab-grown coloured diamonds receive a separate laboratory-grown report from GIA, or a report from labs such as IGI, which usually notes any post-growth treatment. GIA also laser-inscribes the girdle (the thin outer edge) of lab-grown stones it grades to show they are laboratory-grown. Lab-grown coloured diamonds are real diamond, with the same hardness and refractive index as natural; they simply come from a laboratory rather than the ground, and they put strong colours such as pink, blue and red within reach of most budgets.

There is a practical setting point here too. Irradiated colours, in treated natural and lab-grown stones alike, can shift if the diamond is heated by a jeweller's torch during ring sizing or claw re-tipping. Always tell your jeweller when a coloured diamond is treated or lab-grown, so the stone can be removed or protected before any heat work.

Why are Argyle pink diamonds so rare?

Australia has a special place in the coloured diamond story. The Argyle mine in the Kimberley region of Western Australia began full-scale production in the mid-1980s and became the world's main source of pink diamonds, supplying the large majority of all pinks ever mined. Even so, pinks were only a tiny fraction of Argyle's output. Most of what it produced was brown, champagne and cognac diamond, along with very small numbers of red, violet and blue stones.

Rio Tinto closed Argyle in November 2020 once the ore body was worked out. With no comparable source to replace it, the supply of new natural pink diamonds has shrunk sharply. Most Argyle pinks are small, often well under a quarter of a carat, so many are set as accents beside a white centre rather than as the centre stone. Argyle pinks sold through the mine's channels usually came with Argyle documentation and a girdle inscription, which is worth asking about if a stone is described as Argyle.

Argyle also changed how brown diamonds are seen. It promoted a champagne and cognac scale, from C1 (lightest) to C7 (darkest), which helped warm brown diamonds become a popular choice for everyday jewellery. Champagne stones suit rose and yellow gold particularly well, as the next section shows.

Which metal suits coloured diamonds of each hue?

A diamond behaves like a set of mirrors. Light enters, bounces off the back facets and returns to your eye, and some of that light has first reflected off the metal under and around the stone. Yellow gold returns warm yellow light, rose gold returns pinkish light, and platinum and white gold return neutral white light. In a colourless diamond the effect is small, as our guide to how the ring metal changes the colour you see explains. In a coloured diamond it can be the difference between a pink that reads pink and one that reads peach.

Platinum, usually sold as 950 platinum (95% pure), is naturally white and dense, so claws hold well and wear slowly. 18ct white gold is 75% gold alloyed with white metals and usually rhodium plated for a bright white finish; the plating wears and is typically renewed every one to two years, depending on how hard the ring is worn. 18ct yellow gold and 18ct rose gold are also 75% gold, with rose gold's colour coming from copper. 9ct and 14ct golds are paler in colour and a little harder, and suit everyday rings on a tighter budget.

The traditional answer for yellow and pink diamonds is a two-tone ring: a platinum or white gold band with a yellow or rose gold head (the part that holds the stone). You get the colour boost where light enters the diamond and a neutral, hard-wearing band. Black diamonds are often set in black rhodium-plated white gold, which makes the metal almost disappear around the stone, though the black plating wears on high spots and needs renewing.

What is the best setting for coloured diamonds?

The setting does two jobs for a coloured diamond: it keeps the stone safe, and it decides how much metal, light and contrast surround the colour. Here is how the main styles compare.

For yellow diamonds, a long-established approach is a halo of small yellow diamonds set in yellow gold around a Fancy Light or Fancy yellow centre, so the whole head reads as one strong colour. For pinks and blues, the opposite often works better: a halo or side stones of colourless diamond in platinum, which frames the colour without tinting it.

Closed-back settings were common in antique jewellery because they deepen colour, but they block light from underneath. Any film of skin oil, soap or moisturiser trapped behind the stone dulls the colour quickly, so a closed back needs soaking and a soft brush more often than an open setting.

For the detail of claw count, claw thickness and seat depth, our complete guide to diamond and gemstone settings goes through each style. Designing a secure setting for a coloured stone covers the extra care that brittle and treated stones need, and if you work with your hands, see low-profile ring settings for active hands.

Which settings suit each coloured diamond shape?

Coloured diamonds are most often cut as radiants, cushions, ovals, pears and hearts, because these shapes hold colour better than a round brilliant. The shape decides where the fragile corners and points are, and that shapes the setting as much as the colour does.

• Cushion and radiant: the classic shapes for yellow and pink. Four double claws or a halo both work well; see cushion settings, from double claws to halos.
• Round: a round coloured diamond can look paler than the same rough cut as a cushion, so tinted claws or a coloured halo help. Compare options in settings for round diamonds.
• Princess: four sharp corners need V-claws or corner claws; read about protecting a princess cut's corners.
• Asscher: the step facets show colour evenly but also show inclusions, so choose clean stones; see asscher cut setting styles.
• Pear, marquise and heart: each point needs a V-claw or bezel. See pear setting options, marquise settings that guard both tips and how to set a heart diamond safely; pink hearts are a popular choice.
• Ovals and other long shapes: east-west and bezel settings suit these well; see settings for ovals and other elongated shapes.
• Antique cuts: old mine cuts often show a soft natural yellow tint, which yellow gold flatters; see settings for old mine cut diamonds.

Are coloured engagement rings practical for everyday wear?

A coloured diamond engagement ring is as hard-wearing as a colourless one, because the stone is still diamond. The exceptions come from the way some stones are coloured, not from the colour itself. For design ideas across every hue, see our page on choosing a fancy coloured diamond engagement ring. The points to plan for:

• Black diamonds: heavily included and more brittle than other diamonds. A bezel or well-protected claws, and no hammer-style setting pressure on the stone, reduce the risk of chipping.
• Coated diamonds: the colour sits in a thin surface film that can scratch or wear away. Ultrasonic cleaners and harsh chemicals can damage it, so these suit occasional-wear pieces rather than daily rings.
• Irradiated and HPHT-treated stones: stable in normal wear, but tell your jeweller before any sizing or re-tipping that involves heat.
• Plating: white gold and black rhodium need re-plating over time; yellow gold, rose gold and platinum do not.
• Coloured gemstone alternatives: sapphire (9 on the Mohs scale) is durable for daily wear, but softer stones such as morganite (7.5–8) need more protective settings.

For daily wear, the safest combination is a lower-profile head, claws or a bezel in a hard-wearing metal, and a yearly check of claws and settings. Rose gold is a practical choice for pink and champagne stones, as its copper content makes it slightly harder than yellow gold of the same purity.

How do you choose a setting and metal for a coloured diamond?

1. Read the report. Confirm the hue, modifier, intensity grade, and the colour origin line: natural, treated, undetermined or lab-grown.
2. Note the intensity. Fancy Vivid and Fancy Deep stones hold colour in any metal; Light and Fancy Light stones benefit most from a matching metal or halo.
3. Test the metal in daylight. Hold the loose stone against yellow, rose and white metal and choose the one that shows the colour the way you like it.
4. Consider a two-tone head. Coloured gold claws or bezel for the colour, platinum or white gold for the band if you prefer a neutral look.
5. Match the setting to the shape and stone. V-claws for points, corner claws for princess cuts, bezels for black diamonds and active hands.
6. Plan for care. Ask about cleaning closed backs, re-plating, and whether the stone is heat-sensitive before any future sizing.