The 4 Cs, simply explained

1. Carat — the weight

Carat is weight, not size: one carat is 0.2 grams. Bigger carats cost much more per carat, because large diamonds are rarer. Two diamonds of the same carat can look different sizes depending on their shape and cut — an oval or pear looks larger than a round of the same weight.

Tip: prices jump at “magic” weights like 1.00 ct and 1.50 ct. A 0.90–0.99 ct stone looks almost the same and can cost noticeably less.

2. Colour — how white it is

Graded from D (completely colourless) to Z (light yellow). We sell D to M.

• D–F: colourless. The whitest and rarest.
• G–J: near colourless. Look white to almost everyone, especially once set — often the best value.
• K–M: a faint warm tint you may notice. Lovely in yellow or rose gold.

Grades on our site: D · E · F · G · H · I · J · K · L · M

3. Clarity — how clean it is inside

Almost every diamond has tiny natural marks. Clarity grades how many there are and how visible.

• FL — Flawless
• IF — Internally flawless
• VVS1 — Very, very slightly included
• VS1 — Very slightly included
• SI1 — Slightly included
• I1 — Included

Tip: VS1 and VS2 diamonds look completely clean without a magnifier. Paying more for VVS or FL buys rarity, not visible beauty.

4. Cut — how well it sparkles

Cut is about how well the diamond’s angles and proportions return light to your eye. A well-cut diamond looks brighter and livelier, and can even look bigger. Labs give a cut grade for round diamonds (Ideal or Excellent is best). For other shapes they don’t, so we show “Not graded” and you can judge by polish, symmetry, photos and our advice.

Where to spend your budget

1. Cut first — it’s what makes a diamond beautiful.
2. Then the size you want.
3. Then colour: G–H looks white for most people.
4. Clarity last: “eye clean” (often VS2 or SI1) is all you need.