Characteristics
The core quality factors — carat, cut, color, and clarity — that drive diamond pricing.
The diamond trade evaluates every stone against a small set of standardised characteristics that together determine its market price. The four most widely used — carat, cut, color, and clarity — are commonly referred to as the 4 Cs. Each describes a distinct property, each is measured independently, and each contributes non-linearly to the price per carat.
What's in this section
Each article combines a definition, the grading system used by the trade, and the pricing implications visible in the live market data on Stone Insights.
- Carat — how weight translates into price, and why the curve steps rather than climbs.
- Cut — the only characteristic that measures workmanship, and the one shape it is graded on.
- Color — the
D–Zscale, where the price breaks fall, and which shapes hide tint. - Clarity — the grading scale, eye-clean thresholds, and where the market stops paying.
- Shape — the ten commercial shapes, the structural round premium, and where fancy value sits.
- Fluorescence — the modifier that discounts some stones and improves others.
In this section
Carat
How diamond weight is measured, why it's not the same as visual size, and how weight thresholds shape pricing in the trade.
Clarity
How the 11-grade clarity ladder works, what "eye-clean" really means, and how the market prices the gap between laboratory grade and real-world visibility.
Color
How the D–Z grading scale works, why the differences are nearly invisible at the top of the ladder, and how the market prices tint in the real world.
Cut
What cut grade actually measures, how proportions drive light performance, and why cut is the one characteristic that cannot be recovered once a stone leaves the faceting wheel.
Fluorescence
The often-misunderstood 5th characteristic — how UV-excited emission affects diamond appearance, why the trade is split on pricing it, and where the real value plays sit.
Shape
The ten commercial diamond shapes, why round brilliant commands a structural premium, and how to find consistent value in fancy shapes.