Diamond guide

Choose a diamond in the right order: appearance, origin, documentation, then the finer differences in specification. This guide takes you from an initial preference to a clear total price.

1. Start with the complete ring

Set one budget for the diamond, setting and any additions. If the product page shows a setting price and asks you to choose the centre diamond in the next step, the diamond price must be added. Confirm the final total before ordering.

2. Choose an origin

A natural diamond formed through geological processes. A lab-grown diamond is produced through HPHT or CVD processes. They have essentially the same chemical, crystal, optical and physical properties, but differ in origin and in how they formed or were produced. Read the grading report separately for the individual stone.

3. Choose shape before fine-tuning

Shape changes a ring’s silhouette more than a small move along the colour or clarity scale. A round brilliant has a different light pattern from an emerald- or Asscher-cut diamond. Oval, pear and marquise stones create a longer line on the finger. See every diamond shape.

4. Use the 4Cs together

• Cut describes proportions, facets, finish and the return of light.
• Carat is weight, not a direct measure of visible size.
• Colour describes the degree of colourlessness within D–Z, with a separate system for fancy colours.
• Clarity describes internal and external characteristics at 10× magnification.

5. Read the grading report

The report must match the individual stone. Check the laboratory name, report number, measurements, carat, colour, clarity, polish, symmetry, fluorescence and any treatments. Report formats differ between GIA, IGI and other laboratories. Read what a diamond certificate or grading report actually shows.

6. Look in several types of light

Shop lighting, daylight and softer indoor light create different impressions. View the stone while still and in motion. With fancy shapes, also assess the outline, symmetry and any dark areas, such as a prominent bow-tie effect in oval, pear and marquise stones.

7. Check what is supplied

• Which laboratory issued the report?
• Will you receive it digitally, on paper or both?
• Is the report number laser-inscribed on the girdle, and has that been verified for this stone?
• Has the stone been treated?
• Which warranty and return terms apply to the finished ring?

Compare at your own pace

Find diamonds when you are ready to compare. If two reports look alike but the stones still feel different, you can book a complimentary consultation and review them with us.