What Makes a Diamond Good?

A good diamond is one that looks bright, clean and lively on your hand, not one that simply scores top marks on paper.

Choosing a diamond comes down to three questions. How does it look in real life? Is the quality verified? And does it suit the piece you’re buying it for? A 0.10-carat stone in a nose pin and a centre stone in a ring are judged very differently.

Understanding the 4Cs

The 4Cs are the global language of diamond quality: cut, colour, clarity and carat.

For a deeper look at each grade, read our guide to the diamond 4Cs explained.

Which Diamond Characteristics Matter Most?

If you only remember one thing from this diamond quality guide, make it this: cut first, everything else second.


A well-cut diamond hides minor colour and clarity differences because it throws back so much light. A poorly cut one looks dull even with perfect grades. After cut, balance colour and clarity against your budget, and leave carat for last. For reference, the lab-grown options on Aspiri’s solitaire pieces are listed at EF colour and VVS–VS clarity, comfortably eye-clean.

Shape matters too. Oval, pear and marquise shapes look larger than a round diamond of the same weight. Round brilliants tend to give the most sparkle. Emerald and cushion cuts have a softer, more vintage glow.

You can compare these shapes side by side in Aspiri’s solitaire studs, including the Ovalisse Diamond Solitaire Stud Earrings, Lunessa Cushion Diamond Solitaire Studs and Esmera Emerald Diamond Solitaire Studs.

Natural vs Lab-Grown Diamonds

Both are real diamonds with the same chemical makeup, hardness and sparkle. The difference is origin: natural diamonds form underground over millions of years, while lab-grown diamonds are created in a controlled environment. Lab-grown diamonds usually cost less for the same size and grade, which lets you buy a bigger or better-graded stone within the same budget.

Our comparison of lab-grown vs natural diamonds covers the trade-offs in detail.

How to Choose a Diamond for Jewellery

The piece you’re buying changes the priorities.

• Rings: the centre stone gets looked at closely, so cut and clarity matter most. The Solvra Round Solitaire Diamond Ring is a classic example of a single round stone doing all the work. Browse more in our rings collection.

• Earrings: they’re seen from a distance, so you can relax clarity slightly and put that    budget into size or a matching pair. Explore diamond earrings.

• Nose pins: the stones are small, so a clean, secure setting matters more than grade. A bezel setting, like the Classic Bezel Solitaire Stud Nose Pin, protects the stone during daily wear.

• Pendants: the diamond sits flat on the chest, so shape and setting height shape the look.

Always check the certificate. It should state the diamond type and quality grades you’re paying for. Our diamond certification guide explains how to read one.

Common Diamond Buying Mistakes

•  Chasing carat over cut.
A bigger, badly cut stone looks smaller and duller.

• Overpaying for invisible grades.
D colour and flawless clarity look almost identical to G and VS in everyday light.

•  Skipping the certificate.
Without one, you have nothing in writing.

•  Ignoring the setting.
Tall prongs catch on clothes; low settings suit daily wear.

• Setting no budget.
Decide your range first so the 4Cs work for you. Our diamond jewellery price guide helps you set a realistic one.

Frequently Asked Questions

• What is the most important factor when choosing a diamond?
  - Cut. It controls brilliance and sparkle more than colour, clarity or carat.
• What colour and clarity grade should I choose?
  - For most jewellery, a colour from D to H and clarity of VS or better will look clean  and white.
• Is a lab-grown diamond a good choice?
  - Yes. It’s a real diamond with the same properties as a natural one, usually at a lower price.
• Which diamond shape looks biggest?
  - Oval, pear and marquise shapes tend to look larger than round diamonds of the same carat weight.
• Do I need a certificate for a small diamond?
  - For larger stones, always. For very small accent stones, look for a certified quality range from the seller.

Related Guides

Want the bigger picture? Our complete diamond jewellery buying guide covers metals, jewellery types, budget and care in one place.