Diamond Guide

What you're choosing, and what it's made of.

Four factors decide how a diamond looks and what it costs, and most people have only heard of one, carat. This is what the other three actually mean, what your stone is made of, and how carat translates to size on the hand.

The Four Factors

What actually changes how it looks

These decide a diamond's grade. Here's what each one means for how the stone actually looks and wears, not just how it's graded.

Cut The Biggest Factor How much light comes back to your eye. Two stones of the same carat and color can look completely different depending on cut alone.

Color D Through Z Near-colorless grades are where most value sits, full brilliance without the premium of true colorless. Metal tone matters here too, see Metal Guide.

Clarity Flawless to Included Above a certain grade, inclusions are invisible without magnification. Paying for clarity you can't see is the most common place buyers overspend.

Carat Weight, Not Size Covered in full further down this page, with a chart showing what each carat weight actually looks like on the hand.

What It's Made Of

The same stone, grown differently

A lab-grown diamond is pure crystallized carbon, identical in chemical composition and crystal structure to a natural diamond. It's grown over a period of weeks inside a controlled lab environment, rather than forming over billions of years underground.

Nothing about how it looks, wears, or sparkles is different. Optically and physically, it behaves exactly like a natural stone. The full detail on how it's grown and how that's disclosed on your certificate is on Certification & Authenticity.

Carat, Explained

Carat measures weight, not width

A carat is a unit of mass, 200 milligrams, nothing more. How large a stone looks face-up depends on its cut, specifically how the proportions distribute that weight across the top of the stone versus down into its depth.

A well-cut stone spreads more of its weight where you can see it. A deeper cut hides weight underneath, so it can weigh the same on paper and still look smaller on the hand. The millimeter values below are standard industry averages for a well-proportioned cut at each carat weight, which is what we work to.

For Comparison

What each carat weight looks like face-up

Approximate face-up diameter for a round, well-proportioned cut.

Carat	Approx. Diameter (mm)
0.10 ct	3.0mm
0.20 ct	3.8mm
0.30 ct	4.4mm
0.50 ct	5.2mm
1.00 ct	6.5mm

~11mm is about a shirt button

~5mm is about a pencil eraser tip

Shapes are to scale relative to each other, not to your screen. Millimeter values are standard industry averages for the carat weight, actual face-up size varies slightly by cut.

Go Deeper