The 4Cs

Carat

Carat is weight, not size. One carat is 0.2 grams, divided into 100 points, so a 0.90ct stone is ninety points.

Two diamonds of the same weight can look different face-up. Depth carries weight you cannot see from above, and elongated shapes such as oval, marquise and pear spread wider for their weight than a round does. Measurements in millimetres tell you more about apparent size than the carat figure alone, and we print them on every product page.

Prices step up at the round weights. A 0.90ct and a 1.00ct sit roughly a millimetre apart across the top, and the price gap is larger than that difference looks on a hand.

Colour

Colour grading measures the absence of colour, from D at the top of the scale downwards. Venera stocks D to J.

• D, E, F — colourless. No warmth visible, including against white metal.
• G, H, I, J — near colourless. Warmth is detectable when compared side by side with a higher grade, and generally not otherwise.

The setting changes what you see. Yellow and rose gold lend warmth to any stone, so a G to J grade sits naturally in them. White gold is less forgiving, and the difference between an F and a J shows sooner. If your setting is white gold and the budget is tight, colour is the grade to protect.

Clarity

Clarity records the internal features formed during growth, called inclusions, and any surface marks. Venera stocks FL down to SI2.

• FL, IF — flawless and internally flawless. Nothing under ten times magnification.
• VVS1, VVS2 — very, very slightly included. Difficult to find under magnification.
• VS1, VS2 — very slightly included. Visible under magnification, not to the unaided eye.
• SI1, SI2 — slightly included. Visible under magnification and sometimes to the unaided eye, depending on where the inclusion sits.

What matters in wear is whether a stone is eye-clean: nothing visible at normal viewing distance. VS2 and above almost always are. SI grades vary stone by stone, which is why the video matters more than the letters. Emerald and Asscher cuts have large open facets that show inclusions sooner, so they reward a higher clarity grade than a brilliant cut of the same weight.

Cut

Cut is the one grade that describes workmanship rather than the stone itself. It measures how well the proportions return light to your eye. A well cut stone of a modest colour grade will usually outperform a poorly cut stone of a higher one.

Round diamonds carry an overall cut grade: Ideal, Excellent, Very Good or Good. Fancy shapes do not. There is no agreed proportion standard for an oval or a pear, so laboratories grade polish and symmetry but leave the overall cut grade off the report. On those stones, judge the 360° video, read the polish and symmetry grades, and check the length-to-width ratio against the ranges on our shapes page.

This is why the cut row is missing from some of our spec tables. The grade is not hidden; it does not exist for that shape.

The rest of the report

Four letters do not cover everything a certificate states.

• Polish and symmetry — the quality of the finish and the alignment of the facets. Excellent or Very Good on both is what to look for.
• Fluorescence — whether the stone glows under ultraviolet light. At None or Faint it has no practical effect on how the diamond looks in daylight.
• Table and depth percentages — the proportions behind the cut grade, given as numbers so you can compare two stones directly.
• Measurements — the physical dimensions in millimetres. The most honest guide to how large a stone will look.

Where to spend

If something has to give, cut is the last grade to compromise on a round, because it governs how the stone behaves in light. Colour can be relaxed in yellow or rose gold. Clarity can be relaxed wherever the stone is eye-clean, and the video will tell you. Carat is the easiest place to save: stopping just short of a round weight costs you a fraction of a millimetre.

Every stone we sell is certified and every report is linked. You do not have to take our word for any of this.