30/09/2026
Our Founder and CEO shares why the cut of a diamond is the truest measure of its value, and how Astrea London goes further than any grading standard in the world.
Gemmologists have long assessed diamonds using the 4Cs: cut, colour, clarity and carat. Yet of these four, the cut is arguably the most important, because the cut determines how a diamond interacts with light. Two diamonds of identical colour, clarity and carat weight can look entirely different in the hand, and the cut is the reason why.
Colour is measured on a scale from D, the rarest and most colourless grade, to Z. At , we source exclusively in DβE colour, the two highest grades on the scale. This alone represents the top 1% of diamonds available in the world.
But even the finest colour can be lost to a poorly cut stone. Which is why we do not stop at the 4Cs.
Every Astrea diamond undergoes advanced Light Performance analysis, a scientific study of how light travels into the diamond, reflects internally, and returns to the eye. Using tools such as ASET (Angular Spectrum Evaluation Tool) and Ideal-Scope, we can measure three critical properties with precision the 4Cs cannot capture: brilliance is the white light returned to the eye, fire is the dispersion of that light into its spectral colours, and scintillation is the play of contrast as the diamond moves.
When a diamond meets our standard for all three, it enters a tier of true rarity. Precisely cut. Optically flawless. Verifiably extraordinary.
This is why every Astrea diamond is also cut to Hearts and Arrows optical symmetry, achieved by only the top 1% of diamonds globally, and finished to the Astrea Ideal Standard, inspired by the worldβs most demanding cut benchmark.
This is what modern luxury looks like today: measured, transparent and truly exceptional.
