The 4Cs of Diamonds: Cut, Colour, Clarity & Carat
1. Cut: How a Diamond Handles Light
Cut quality describes a diamond’s proportions, symmetry and polish—not its shape. A well-cut diamond returns light effectively and can look brighter than a poorly cut diamond of the same carat weight.
- Prioritize: overall cut grade, proportions, symmetry and polish.
- Compare in motion: video or an in-person view can reveal brightness, fire and dark areas.
- Fancy shapes: proportions and visual inspection matter because grading approaches vary by shape and laboratory.
2. Colour: From D to Z
The widely used D-to-Z scale describes the absence or presence of body colour in diamonds outside the fancy-colour range. D is the highest colourless grade; colour becomes progressively more noticeable toward Z.
- D–F: colourless grades.
- G–J: near-colourless grades that can offer strong value, depending on the setting and metal.
- K–Z: increasingly warm colour that some buyers prefer.
Compare diamonds in consistent lighting and consider how the setting colour affects their appearance.
3. Clarity: Inclusions and Blemishes
Clarity grades describe internal inclusions and surface blemishes viewed under standardized conditions, usually at 10× magnification.
- FL–IF: no inclusions visible at 10×; IF may have surface blemishes.
- VVS1–VVS2: inclusions are very difficult to see at 10×.
- VS1–VS2: minor inclusions that are often difficult to see without magnification.
- SI1–SI2 and I1–I3: inclusions are progressively easier to see and may affect appearance or durability.
An “eye-clean” diamond can offer good value, but inspect the location and type of inclusions as well as the grade.
4. Carat: Weight, Size and Proportion
Carat measures weight, not face-up diameter. Two diamonds with the same carat weight can look different in size because of their shape and proportions.
- Compare dimensions: millimetre measurements show how large a diamond faces up.
- Balance the 4Cs: a slightly lower carat weight can leave more budget for cut quality or the setting.
- Expect non-linear pricing: price per carat often rises at popular milestone weights, although market conditions and grading details also matter.
For lab-grown diamonds, also review the grading report for growth-related colour nuances, transparency and any post-growth treatment disclosures.
How to Use the 4Cs
The best combination of cut, colour, clarity and carat depends on the shape, setting, budget and features you notice most. Start with cut and overall appearance, then use the grading report to compare diamonds on consistent terms.
Promise Jewelry offers lab-grown and natural diamonds and more than 30 years of family jewelry experience. Bring us the grading reports or specifications you are comparing, and we can explain the trade-offs without treating any single grade as the only right answer.