The 4Cs, in Plain English
Cut, colour, clarity and carat: what each one changes, and what it costs
Read guide 8 min
Diamond grade test
Can you tell the difference?
Two diamonds, one costs more. 10 rounds show you which grades you can actually see in a ring, and which ones you only see on the receipt.
Two diamonds. One costs more. Which?
10 rounds, about three minutes. Each pair differs by one grade. Pick the one you think costs more, or say they look the same if you can't tell. Then we show you what changed, and whether anyone could see it in a ring.
Why we built this
Certificates grade what a lamp sees. You'll see a ring.
Diamond grades are measured under bright lights, with magnification, often with the stone upside down. That's how they get so precise. But nobody wears a diamond upside down under a lamp.
Some of those grade steps make a real difference to how a ring looks. Many don't, and they still change the price. Knowing which is which is the most useful thing you can learn before you speak to a jeweller.
Common Questions
Can you see the difference between diamond colour grades?+
Between neighbouring grades, no. D to G all look white face-up in a ring. Most people only start to notice warmth around I or J in platinum or white gold, and usually only next to a whiter stone. In yellow gold, the metal reflects warmth into the diamond, so colour matters even less.
Can you see the difference between VS1 and VVS1?+
Not without magnification. Both are clean to the eye. The marks in a VS1 are small enough that a trained grader needs a 10x loupe and has to look carefully. SI1 is often still clean to the eye; from SI2 down, check a photo of the actual stone.
Which diamond grade makes the biggest visible difference?+
Cut. It decides how light comes back out of the stone, which is what you see as sparkle. A Good cut looks noticeably flatter than an Excellent cut of the same size and colour. If you are going to spend more on one grade, make it cut.
Are the diamonds in the game real photos?+
No, they are illustrations. We drew them to show what you would notice face-up in a ring at normal viewing distance, not what a grader sees under a lamp. The grades, the explanations and the price differences are real.