Diamond Guide
Choosing a diamond, with confidence
A diamond is a personal choice, not just a set of grades. Whether you’re choosing an engagement ring, marking an anniversary or treating yourself, it helps to understand what you’re looking at.
Our guide explains the essentials without the jargon. Start with the style you love and a budget that feels comfortable, then use the details to compare your options.
Start with what matters to you
Think about how the jewellery will be worn, the shapes you’re drawn to and the setting you prefer. For an everyday ring, consider comfort and how the design fits your lifestyle as well as its appearance.
Our advice: look at the whole piece, not just the carat weight. The diamond, setting and proportions should work together.
The 4Cs, simply explained
Cut: how a diamond handles light
Cut describes the proportions, arrangement of facets and finish that influence a diamond’s sparkle. It is different from shape, such as round or oval.
When comparing diamonds, don’t overlook cut in favour of weight alone. GIA’s overall cut grade applies to standard round brilliant diamonds in its D-to-Z colour range, so other shapes need a different approach to comparison.
Colour: the presence of body colour
For diamonds in the colourless-to-light-colour range, colour grading describes the presence or absence of colour. Consider the stone’s appearance alongside your chosen metal and setting, rather than reading the grade in isolation.
Naturally coloured diamonds are a separate subject and should not be compared in the same way as colourless diamonds.
Clarity: a diamond’s characteristics
Clarity describes internal characteristics, called inclusions, and surface features, called blemishes. Their size, number and position help determine the grade, assessed under 10× magnification.
A clarity grade is not the same as what you notice at normal viewing distance. Ask how the particular stone looks, rather than choosing by a grade alone.
Carat: weight, not a measurement of width
Carat measures a diamond’s weight. It does not tell you everything about its visible size or appearance: dimensions, shape and proportions matter too.
When comparing jewellery, check whether the stated weight refers to one diamond or the combined weight of several stones.
Finding a shape you love
Round, oval, emerald, princess, pear, marquise and cushion shapes each create a different impression. Shape is a matter of personal taste, and the setting can change the overall look just as much as the stone itself.
Use these shape names as a starting point for exploring styles, rather than as a list of what is currently available.
Comparing diamond shapes and sizes
The chart below illustrates how different shapes compare across carat weights. It is a visual reference, not a guarantee of a particular stone’s dimensions. The image is not displayed at actual size.
Chart credit: DiamondDB. Select the chart to open the larger image and read the measurements.
Natural and laboratory-grown diamonds
Be clear about which you are considering before comparing stones or prices. Ask for the diamond’s origin to be stated clearly and check the supporting documentation.
Grading and assessment formats can differ between natural and laboratory-grown diamonds. Read the document for the particular stone rather than assuming every report uses the same system.
This guide explains the choices; it is not a statement that every option is stocked. Linda can help with questions about a particular piece.
What a grading report tells you
A grading report records a diamond’s assessed characteristics. For example, a GIA natural diamond report can include the 4Cs, measurements, proportions and information about treatments.
Ask which laboratory issued the document, what it covers and whether its details match the stone you are considering. A grading report is not a price guarantee and does not replace looking carefully at the finished jewellery.
Make your budget work for you
There is no need to chase the highest grade in every category. Decide what matters most to you, compare the whole piece and ask where a change in specification would make a visible difference.
For an engagement ring, think about the setting, metal, fit and how it will sit alongside a wedding band. A thoughtful choice should feel right to wear as well as look beautiful.
For further independent reading, visit GIA’s diamond buying guide.
A little personal guidance
You’re welcome to browse and order in your own time. If you’d like help choosing, understanding a report or comparing designs, Linda will be happy to help.