04The secret to quality
A short guide to what makes a diamond beautiful, and how to judge one for yourself: its anatomy, the four Cs, the classic shapes and how to look after it.
01Anatomy
Five words a jeweller will use when they talk about a stone. Select one to see where it is.
02The secret to quality
Every diamond is judged on cut, colour, clarity and carat. Here's what each one means, and what to look for when you choose.
Light returned to the eye 100%
G Near colourless
1.00 ct about 6.5 mm across · weighs 0.20 g
C01
Cut is the one C shaped entirely by hand. It describes how well a diamond's facets work together to send light back to your eye. Too shallow or too deep, and light slips out through the bottom; cut well, and it bounces back up as brilliance and fire.
Try it: changetap or slide the pavilion angle and follow the light.
C02
White diamonds are graded from D, completely colourless, to Z, which shows a light yellow or brown tint. The less colour a diamond has, the more freely light travels through it, and the rarer it is.
Slide along the scale from D to Z.
C03
Almost every diamond carries tiny traces of how it formed: inclusions inside the stone and blemishes on its surface. Clarity is graded from Flawless to Included, judged under 10× magnification.
Move the loupe across the stone to look closer.Tap the stone, or drag sideways, to move the loupe.
C04
Carat measures weight, not size. One carat is exactly 0.2 grams. Two diamonds of the same weight can look quite different depending on how they're cut, so it's worth judging size by eye as well as by number.
Pick a weight to see its approximate size.
See all four side by side, in the showroom.
03Shapes
Shape is the outline of a stone seen from above. Each one handles light a little differently.
The most popular shape, cut with 57 or 58 facets to send back as much light as possible.
A square with crisp, pointed corners and a brilliant-style sparkle.
A square or rectangle with softly rounded corners, like a pillow.
An elongated brilliant with a soft, classic outline.
Round at one end and pointed at the other, like a falling drop.
A step cut with long, flat facets that shows off a stone's clarity like a hall of mirrors.
04Care
Five habits that keep jewellery looking the way it did on the first day.
Put jewellery on after perfume, hairspray and lotion, and take it off before bed.
Take rings and bracelets off before swimming, the gym, gardening or housework.
Diamonds can scratch other jewellery, and each other. Keep pieces in separate pouches or compartments.
Warm water, a drop of mild soap and a soft brush. Rinse well and pat dry with a soft cloth.
Have prongs and clasps checked from time to time, so a stone never works loose.
05FAQ
Cut, colour, clarity and carat. Together they describe how well a diamond returns light, how much colour it shows, how clean it is inside, and how much it weighs. They are the standard way diamonds are graded and compared.
Many jewellers would say cut, because it has the biggest effect on how much a diamond sparkles. A well-cut stone sends light back up to your eye; a poorly cut one lets it leak out through the bottom, whatever its colour, clarity or weight.
White diamonds are graded from D, completely colourless, to Z, which shows a light yellow or brown tint. D to F are colourless, G to J near colourless, K to M faint, N to R very light, and S to Z light.
Diamonds graded VS (very slightly included) usually look clean without magnification, because their inclusions are hard to see even at 10×. SI diamonds can sometimes show inclusions to the naked eye, and diamonds graded I usually do.
A well-cut round brilliant of 1 carat is about 6.5 mm across. A carat is a unit of weight, 0.2 grams, so two diamonds of the same weight can look different sizes depending on how they are cut.
Usually 57, or 58 when the point at the bottom (the culet) is cut as a tiny flat facet.
Soak it in warm water with a drop of mild soap, brush gently with a soft brush, then rinse well and pat dry with a soft cloth. Store pieces separately, because diamonds can scratch other jewellery.
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