From DiamondWatcher.com, where you can compare diamond prices across retailers.
Carat (Size)
Carat is weight. One carat is 200 milligrams. Price climbs much faster than weight because big rough is rare, and it jumps again at round numbers like 1.00ct, 1.50ct and 2.00ct, the weights people search for. In October 2026 a natural 1 carat round (G, VS1) had a median price of $3,419. At 1.5 carats it was $8,763, about 2.6 times the price for 1.5 times the weight. Lab-grown is much flatter: $350 at 1 carat, $613 at 1.5. Our Diamond Price Index tracks that carat cliff every month.
Face-up size for a well-cut round brilliant. Shape and proportions shift it a little. See every size from 0.25 to 5 carats in our diamond size chart →
Two 1 carat rounds with different proportions can face up at noticeably different sizes, and shape changes it again. Oval vs Round and Round vs Princess compare face-up size at the same weight, and the diamond size chart shows every carat in mm and on the hand.
Cut (Sparkle)
Cut grades a diamond's proportions, symmetry and polish, whatever its shape. It controls how light enters the stone and bounces back out through the top, so it's the grade behind brilliance, fire and sparkle.
Sweet spot: Very Good to Excellent. A badly cut diamond looks dull even at D color and Flawless clarity.
This is the grade we'd hold firm on. A weak cut makes a stone look lifeless whatever its other grades say, and an Excellent cut will carry a G color or an SI1 clarity without anyone noticing.
Clarity (Flaws)
Clarity grades inclusions inside the stone and blemishes on its surface, judged under 10× magnification. Most grades in the middle of the scale look clean to the naked eye. A VVS and a VS2 stone look the same face-up, and you'd need a loupe to tell them apart.
Sweet spot: VS2–SI1. See our VS1 vs VS2 and SI1 vs SI2 guides for exactly where the visible line falls.
Visible under magnification, and sometimes to the naked eye, depending on the inclusion's size and where it sits.
No internal flaws under 10× magnification. A premium grade most buyers don't need.
Color (Tint)
Color grades how little tint a diamond has. GIA's scale runs from D (colorless) down to Z (light yellow or brown), and a whiter stone lets light through more cleanly, which adds brilliance.
Sweet spot: G–H. See our G vs H Color guide for when the difference becomes visible.
A faint warm tint. You notice it most in white gold or platinum, and in bigger stones.
No visible color at all. It's the top grade, and more than most buyers need.
How They Work Together
A bigger diamond shows inclusions and tint more easily, so at 2 carats and up it can make sense to spend more on clarity and color. Shape matters too. Round, oval and cushion are brilliant cuts that hide both better than step cuts like emerald or asscher, and the same SI1 can look clean in one shape and visible in another. See Oval vs Cushion for how that plays out between two popular shapes.
How you weigh the four comes down to budget and what your eye picks up. If you can, put a few stones at your target grades side by side, an H next to a G for example, before paying for the grade above.
How DiamondWatcher Helps You Compare in Practice
Once you've picked your grades, DiamondWatcher pulls matching stones from every major retailer into one search.
- Filter by carat, cut, clarity and color
- Compare the same spec across retailers (in October 2026 the median natural 1 carat G / VS1 round was $2,109 at Brilliance and $4,613 at Blue Nile)
- Real listings you can buy today
Search diamonds by grade to see what your combination costs right now.