The Dominium Diamond Guide
Choose a diamond worth passing down.
A clear, honest guide to how diamonds are graded, the shapes we work with, natural and lab-grown stones, and the standard every Dominium diamond must meet.
Our Approach
A certificate tells you what a diamond is. Not how it feels to wear.
We read every grading report closely, then we look past it. Each stone is chosen for how it holds light in real life, set in 18k gold, on a hand that will wear it for decades.
I
Selected by eye, not only on paper
Two diamonds with identical grades can look very different. We review every stone against our house standard and for how it actually looks: its brightness, its sparkle and how evenly it reflects light.
II
Two origins, never blurred
We offer natural and laboratory-grown diamonds. We never mix them in one piece, and we never leave the origin unclear. It is stated on the certificate and in every quote we send you.
III
The fifth C: conscience
Beyond the four Cs is the question of where a stone comes from. Our natural diamonds are sourced in line with the Kimberley Process, with a written conflict-free assurance and a documented chain of custody from our suppliers.
The Four Cs
The language of every diamond.
Cut, colour, clarity and carat are how every diamond in the world is graded. Here is what each one means, and where we draw the line.
01
Cut
The biggest influence on sparkle.
Cut describes how well a diamond's facets are angled and finished to send light back to your eye. A well-cut stone looks brighter, livelier and often larger than a poorly cut stone of the same weight. Grades run from Excellent down to Poor.
02
Colour
The whiter, the rarer.
Most white diamonds carry a faint hint of yellow. Colour is graded from D (completely colourless) to Z (light yellow), and the closer a stone is to D, the rarer it is. Neighbouring grades are very hard to tell apart once a diamond is set.
03
Clarity
What matters is what you can see.
Almost every diamond has tiny natural marks inside it (inclusions) or on its surface (blemishes). Clarity is graded under 10× magnification, from Flawless to Included. The real test is simple: nothing should be visible to the naked eye.
04
Carat
Weight, not size.
One carat weighs 0.2 grams and is divided into 100 “points”. Prices jump at round numbers such as 0.50 and 1.00 carat, so a 0.90 ct stone can look almost the same as a 1.00 ct for noticeably less. Shape also changes how big a carat looks.
The colour scale
From D to Z. The bars show the range each Dominium tier accepts.
The clarity scale
From Flawless to Included, judged under 10× magnification. Whatever the grade, every Dominium stone must be eye-clean.
Grades follow the GIA and IGI scales. On small screens, swipe the scales sideways.
Shapes
Find the shape that feels like you.
Shape is the outline of a diamond; cut is how well it is faceted. Every shape has its own character, and its own things to look for.
Round Brilliant
The most brilliant shape of all, faceted for maximum sparkle. Timeless in solitaires, studs and tennis bracelets.
Look forAn Excellent cut grade.
Oval
Elongated and elegant. It looks larger than a round of the same weight and flatters the finger.
Look forA ratio of 1.35–1.50 and little or no “bow-tie”, a dark band across the centre.
Cushion
Soft, rounded corners and a warm, romantic glow with a vintage feel.
Look forA ratio of 1.00–1.10 for a square look.
Pear
A teardrop that joins a rounded end to a single point. Graceful as a pendant, and one half of our Toi et Moi ring.
Look forA ratio of 1.50–1.75, even shoulders, and a point protected by a claw.
Marquise
Long and pointed at both ends, it looks the largest of any shape for its weight.
Look forA ratio of 1.75–2.25 and both points protected.
Emerald
Step-cut with long, open facets that give a calm “hall of mirrors” flash rather than sparkle.
Look forA ratio of 1.30–1.50 and higher clarity, as the open facets show more.
Radiant
The clean, cropped outline of an emerald with the lively sparkle of a brilliant.
Look forA ratio of 1.00–1.05 for square, or 1.20–1.35 for rectangular.
Heart
The most romantic shape, and one that needs real skill to cut well. It reads best from around half a carat.
Look forEven, rounded lobes and a crisp, clear cleft.
Natural or Lab-Grown
Both are real diamonds. They are not the same choice.
A lab-grown diamond has the same chemistry, hardness and sparkle as a natural one. The difference is origin, rarity and long-term value, and we will always tell you which is which.
Heritage · Signature
Natural
- Origin
- Formed deep in the earth over one to three billion years.
- Rarity
- Finite and genuinely rare, especially in the top grades.
- Price
- Higher, reflecting that rarity.
- Value
- Tends to hold its value better than lab-grown over time.
- Certificate
- GIA (Heritage) or IGI (Signature).
- Choose it for
- An heirloom whose story began long before yours.
Contemporary
Laboratory-grown
- Origin
- Grown in weeks, using CVD or HPHT technology.
- Rarity
- Produced to order, so supply is not limited.
- Price
- A fraction of a natural stone of the same size and grade.
- Value
- Prices have fallen sharply in recent years; very little resale value.
- Certificate
- IGI, with origin and growth method stated.
- Choose it for
- A larger or whiter stone for your budget, made to be worn every day.
Because top colour and clarity cost very little extra in a lab-grown stone, we hold our lab-grown diamonds to a higher technical standard than most of the market: D to F colour, VS1 or better, and never a tinted or visibly included stone.
The Dominium Standard
Three tiers. One bar for beauty.
Every diamond we set belongs to one of three tiers. Each line below is a minimum. No stone falls beneath it.
Natural · The apex
Heritage
Exceptional natural diamonds for pieces made to be passed down. Top colour, very high clarity, and traceable origin wherever it is available.
GIA certifiedNatural · The house standard
Signature
The heart of Dominium bespoke work. Fine natural diamonds, always eye-clean, chosen for brightness and balance in 18k gold.
IGI certifiedLaboratory-grown
Contemporary
Larger stones and bolder designs at an accessible price, held to a deliberately high technical standard. Origin always stated plainly.
IGI certified| At a glance | Heritage | Signature | Contemporary |
|---|---|---|---|
| Origin | Natural | Natural | Laboratory-grown |
| Cut | Excellent cut, polish & symmetry | Excellent cut, polish & symmetry | Excellent cut, polish & symmetry |
| Colour | D–F | D–H | D–F |
| Clarity | VVS2 or better | VS2 or better, eye-clean | VS1 or better |
| Fluorescence | None to Faint | None to Faint | None to Faint |
| Treatments | None | None | Stated on the certificate |
| Certificate | GIA | IGI | IGI |
| Provenance | Traceable origin where available | Documented chain of custody | Growth method disclosed |
Every centre stone of 0.30 ct and above comes with its own independent grading report. Smaller accent diamonds are matched by eye for colour and brightness.
The Finer Details
What experienced buyers look for.
Beyond the four Cs, a few details separate a good diamond from a beautiful one.
Fluorescence
Some diamonds glow blue under ultraviolet light. Strong fluorescence can make a stone look slightly hazy in sunlight, so we accept only None to Faint.
No hidden treatments
We never set natural diamonds that have been fracture-filled, laser-drilled or colour-treated. Any treatment on a lab-grown stone is stated on its certificate.
Matched pairs and sets
Earrings, Toi et Moi rings and tennis bracelets need stones that match one another. We pair them for colour, clarity, size and brightness, not just the grade on paper.
Your gold changes the picture
Yellow gold warms a diamond's appearance, so a G or H stone can look beautifully white. White gold shows colour more, so we suggest a higher colour grade there.
Proportions before paper
For ovals, pears, marquise and emeralds, the length-to-width ratio decides the look. Use the ratios in our shape guide as a starting point, then trust your eye.
Check the certificate
Every certified stone has a report number, usually laser-inscribed on its edge. You can check that number on the GIA or IGI website to confirm the report is genuine.
Good to Know
Questions about diamonds.
Is a lab-grown diamond a real diamond?
Yes. It is chemically, physically and optically the same as a natural diamond. The only difference is where it formed, which is why it must always be disclosed. We state it on every certificate and quote.
Can anyone tell natural and lab-grown apart by looking?
No, not by eye and not with a standard diamond tester pen. Telling them apart takes specialised laboratory equipment, which is why an independent grading report matters.
Which shape looks biggest for its weight?
Elongated shapes such as marquise, oval and pear spread their weight across a larger surface, so they look bigger than a round diamond of the same carat.
Will my diamond hold its value?
Natural diamonds tend to hold their value better than lab-grown ones, but fine jewellery is rarely a reliable investment, and resale prices are usually well below what you paid. Lab-grown prices have fallen sharply in recent years. Choose the diamond you will love wearing.
Can I approve my stone before it is set?
Yes. For bespoke and made-to-order pieces, we share your stone's certificate and details with you for approval before setting begins.
Do you work with coloured diamonds?
Yes, including yellow and pink. Fancy-coloured diamonds are graded on the strength of their colour rather than the D–Z scale. Tell us what you have in mind and we will source to your brief.
How should I care for my diamond?
Diamond is the hardest natural material, but it can still chip from a hard knock, and oils and lotions dull its sparkle. Clean it gently with warm water, mild soap and a soft brush. See Warranty, Care & Repairs.
Ready to Choose?
Let's find your stone together.
Tell us the shape, size and budget you have in mind. We will source options to the Dominium standard and talk you through each one.
Need your size too? Ring Size Guide
Natural or lab-grown, the origin of every Dominium diamond is always stated plainly.