A short, honest guide to diamonds.

Cut is the only one of the four C's that's really non-negotiable. It's the geometry of the stone, the angles and proportions that decide how light moves through it. A well-cut one-carat diamond will out-sparkle a poorly-cut two-carat one, every time.

For round brilliants there's a graded cut score (Excellent, Very Good, Good, etc.). Anything below Excellent on a centre stone, we won't source. For other shapes (oval, emerald, marquise) the cut isn't graded the same way, so we look at proportions ourselves and reject anything that looks dull through a loupe.

Translation: don't sacrifice cut to get more carat. The stone will look smaller anyway.

Carat is weight, not size. One carat is 0.2 grams. A round brilliant at 1.00 ct is roughly 6.5 mm across the top. At 1.50 ct it's about 7.4 mm, only 14% wider. Real-world size grows slowly as you go up the carat ladder, even though the price climbs quickly.

There are price thresholds at the round numbers: 0.50, 0.70, 1.00, 1.50, 2.00. A 0.95 ct stone costs noticeably less than a 1.00 ct stone of the same quality, and looks effectively the same. If you're working to a budget, ask us about under-the-line stones.

Bigger isn't always better. A 0.7 ct centre stone on a slender finger reads more elegantly than a 1.5 ct one. It's worth seeing both in person.

The shape is the outline of the stone. It changes how a diamond wears and reads on the hand as much as any grade does.

• Round brilliant remains the most brilliant cut, because it reflects the most light.
• Oval appears larger than its actual carat weight.
• Emerald emphasises clarity and clean lines.
• Radiant combines sparkle with a rectangular silhouette.
• Cushion offers softer proportions and a vintage feel.
• Pear elongates the finger.
• Marquise maximises finger coverage.
• Princess offers a sharp, modern square shape.

Antique and specialist shapes

Beyond the eight shapes we photograph, we source and set antique and specialist cuts to order. They are not in the configurator because each one is found for a particular ring rather than picked from a list.

• Old European the brilliant of the early twentieth century, cut by hand with a small table, a taller crown and an open culet you can see straight down into. It returns light in broad, slow flashes rather than the fast scintillation of a modern round, which is why antique rings read softer under candlelight and warm lamps.
• Old Miner also called the old mine cut, the squarish cushion that came before the Old European. It was cut to follow the rough rather than a formula, so the corners are gently rounded, the facets rarely match exactly, and no two stones are alike. Chosen for character rather than symmetry.
• Asscher a stepped square with cropped corners and deep, mirrored facets, essentially the square counterpart to the emerald cut. Step cuts hide nothing, so the stone matters more than the grade on paper.
• Baguette a slim rectangle with straight step facets. Rarely a centre stone. Used in pairs flanking one, or in a line along a band.
• Trapezoid a tapered four-sided stone cut to flank a centre diamond, meeting it flush along the long edge.
• Half-Moon a shoulder stone, flat along one side and curved along the other, so it sits tight against the centre stone.
• Heart a modified brilliant judged almost entirely on symmetry: an even cleft, matching lobes and a clean point. It needs carat weight for the outline to read clearly, so we rarely suggest one under 0.50 ct.
• Trillion a triangular brilliant with straight or gently rounded sides. It spreads wide for its weight, so it looks larger than the carat figure suggests.

Diamond colour is graded D (perfectly colourless) through Z (light yellow). The difference between adjacent grades is invisible without a master comparison set, even to a trained eye.

For most stones, F or G is indistinguishable from D once it's set. For a yellow-gold setting, you can comfortably go down to H or I, because the warm metal flatters slight warmth in the stone. Paying for D-E in a yellow-gold ring is paying for something nobody will see.

Clarity describes the small inclusions inside the stone (which all diamonds have, including the very expensive ones). The scale runs from FL (flawless) through I3 (heavily included).

Anything VS2 or better is what's called "eye-clean". You can't see the inclusions without 10x magnification. SI1 stones are often eye-clean too, depending on where the inclusions sit. We'll always check this for you.

Clarity is the easiest place to save money without losing anything visible. We'd rather you spent that money on a better cut.

Lab-grown diamonds are chemically identical to mined ones. Same crystal structure, same hardness, same brilliance. Under a loupe you can't tell them apart without specialist equipment.

What's different is the price? Lab-grown diamonds generally cost significantly less than natural diamonds of comparable quality. The choice often comes down to personal priorities rather than right or wrong.

We don't take a side. Both options are in our configurator, both are sourced with full traceability, and we'll happily talk through the trade-offs in a consultation. Some of our customers prize the geological story of a natural stone. Others prefer to put the savings into a larger stone or a better cut. Both are reasonable.

Every centre diamond is independently certified.

Every centre stone we sell comes with an independent grading report from GIA, IGI, or HRD. It documents the cut, carat, colour, and clarity grades, plus the stone's unique identifier. Keep it with your insurance.

For lab-grown stones, IGI is the standard issuing body. The certificate format is the same.