The 4 Cs are the four criteria by which every diamond is graded: cut (quality of the cut), color, clarity and carat (weight). They apply to every diamond, laboratory-grown diamonds included. For our laboratory-grown diamonds this means: color D to F, clarity VS or better, cut never below Very Good. Every lab-grown diamond from 0.5 carat comes with an IGI certificate; natural diamonds from 0.5 carat come with a GIA report.
The system was developed by the Gemological Institute of America (GIA), where I completed my training. The goal was simple: make diamonds comparable. Uniform standards for a market that used to be opaque and too often depended on the seller's judgment.
I will explain what lies behind each C, and what you should really look for when buying.
What does cut mean for a diamond?
Cut describes the quality of the cut: how well a diamond refracts light and sends it back. Cut is not the shape. Round, Oval, Pear, Emerald: that is the shape of the stone. The cut decides whether that shape shines.
A stone with perfect color and clarity but a weak cut looks dull. A stone with average grades and an excellent cut catches the light and returns it in small flashes. When I select a stone, I always start with the cut. The rest follows.
The scale: Excellent, Very Good, Good, Fair, Poor. At ANNARELLE: never below Very Good.
What does color mean, and why D to F?
Color measures how much tint a white diamond has. The less color, the higher the grade. The scale starts at D, completely colorless, and runs to Z, visibly yellowish.
D, E and F are the three highest grades, the group of colorless stones. At ANNARELLE we use only these three. With lab-grown diamonds, this quality fits a budget that would land you further down the scale with a mined stone. For us, that is the real advantage: better stone quality, not a lower price.
Colored diamonds follow their own rules. Read more in our article on colored lab-grown diamonds.
What does clarity mean?
Clarity describes how many inclusions a diamond has, and how large they are. Almost every diamond carries small traces of its growth. Most of them are invisible to the naked eye.
The scale runs from FL (Flawless) to I3 (Included). In VS1 and VS2 stones, inclusions are hard to find even under ten-times magnification. When you wear the piece, you will not see them. Every laboratory-grown diamond at ANNARELLE is VS or better.
What does carat mean?
Carat is a unit of weight, not of size: one carat equals 0.2 grams. How large a stone looks also depends on its shape and cut.
At the same weight, an oval stone often looks larger than a round one, because its surface is stretched. If you want a piece that stands out, do not look at the carat number alone.
For a tennis bracelet, the carat number matters least of all. We explain why in our article on the quality of tennis bracelets.
Do the 4 Cs apply to lab-grown diamonds?
Yes. Lab-grown diamonds are made of pure carbon, have a hardness of 10 and are graded by IGI against the same 4 Cs as mined diamonds. They cannot be told apart with the naked eye; only specialist labs can determine the origin.
Why we deliberately choose lab-grown diamonds: read Lab-grown diamonds: the smart choice.
What does the IGI certificate show?
The IGI certificate documents the 4 Cs of a single stone, independently graded by the International Gemological Institute. At ANNARELLE, every stone from 0.5 carat comes with one. Very small stones, such as in a pavé setting, are not certified individually, as is standard in the industry.
The report number is on your invoice after purchase. You can verify it at any time on the IGI website.
The ANNARELLE standard at a glance
| C | Scale | At ANNARELLE (lab-grown) |
|---|---|---|
| Cut | Excellent to Poor | never below Very Good |
| Color | D to Z | D, E, F |
| Clarity | FL to I3 | VS or better |
| Carat | weight, 1 ct = 0.2 g | IGI certificate from 0.5 ct |
What this means for your purchase
The 4 Cs give you guidance. They protect you from bad purchases and help you compare stones. But they do not replace the eye of someone who knows what matters.
At ANNARELLE, I personally check every stone selection. The certificate alone is not enough for me. What I hold in my hand has to feel right. You will find our pieces with white lab-grown diamonds in BLANC.
And if you are looking for a ring: we explain what matters in Buying a diamond ring.
Pour toujours.
