---
title: "The four Cs of diamonds"
description: "The four Cs of diamonds: carat weight, color, clarity and cut. What each C measures, how a lab grades it, and how much it changes the look of a stone."
url: https://digitalgemology.com/learn/four-cs
image: https://digitalgemology.com/img/learn/ngidqkrLg00.jpg?v=b97aade1
---

> Markdown copy of https://digitalgemology.com/learn/four-cs. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons.
> Site index: https://digitalgemology.com/llms.txt

[Learn](https://digitalgemology.com/learn)

# The four Cs of diamonds

Eight lessons · three videos · read them in any order

The four Cs are color, clarity, cut and carat weight: four scales that give diamonds a shared language. These pages explain what each C measures, its scale and how a lab grades it. In our 3D Gemstone Simulator and Cut Grading Tool, you change one C at a time and see how much it changes the look of a stone.

New here? Start with [Carat weight vs size: why a 2 ct diamond isn't twice as big](https://digitalgemology.com/learn/four-cs/carat-weight-vs-size).

1. 1 · Article
  ## [The 4 Cs of diamonds explained: carat, color, clarity and cut](https://digitalgemology.com/learn/four-cs/the-four-cs-explained)
  The four scales, what each one measures, how a lab grades it, and which C changes the look of a stone most.
2. 2 · Animated explainer
  ## [Carat weight vs size: why a 2 ct diamond isn't twice as big](https://digitalgemology.com/learn/four-cs/carat-weight-vs-size)
  Why double the carat weight is only 26% wider, with a T73 size chart in mm from 0.25 to 5 ct.
3. 3 · Article
  ## [The diamond color scale, D to Z: where you first see a tint](https://digitalgemology.com/learn/four-cs/diamond-color-scale-d-to-z)
  What each range from D to Z looks like, how a lab grades color, and why warm light hides the step from D to H.
4. 4 · Article
  ## [Fancy color diamonds and fluorescence: beyond the Z grade](https://digitalgemology.com/learn/four-cs/fancy-color-diamonds-and-fluorescence)
  What fluorescence is, how often it shows and what it does to the look, plus how fancy color grades work past Z.
5. 5 · Article
  ## [The diamond clarity scale explained, from FL to I3](https://digitalgemology.com/learn/four-cs/diamond-clarity-scale)
  The 11 clarity grades from FL to I3, what decides each grade, and where inclusions start to show without magnification.
6. 6 · Video
  ## [Diamond cut grade: Excellent vs Poor, side by side](https://digitalgemology.com/learn/four-cs/diamond-cut-grade-excellent-vs-poor)
  Excellent and Poor side by side: cut vs shape, the light map, leakage at each grade and the shrinking diamond.
7. 7 · Video
  ## [How a diamond cut grade is set: proportions, polish and symmetry](https://digitalgemology.com/learn/four-cs/how-diamond-cut-grade-is-determined)
  The seven components of a cut grade, why the weakest one wins, and how to take a Poor stone to Excellent.
8. 8 · Article
  ## [Putting the 4 Cs together: which C to spend on](https://digitalgemology.com/learn/four-cs/which-of-the-four-cs-matters-most)
  Which C to spend on: a D Flawless Poor beside an H SI1 Excellent, and bigger vs better cut.

## Quick quiz

Every lesson ends with a few questions. Want more? [The The four Cs quiz](https://digitalgemology.com/skool/quiz/the-four-cs) covers the whole topic, with the answer and the reason after each question.

## Cuts in this topic

We sell the files of these cuts: 3D models and cutting files, with a personal-use license.

- [T73 Round Brilliant Cut](https://digitalgemology.com/cuts/t73-round-brilliant): 3D files and cutting files, €9.99 each

[All topics](https://digitalgemology.com/learn)