The 4Cs of diamonds, made visual
Cut, colour, clarity and carat, explained in plain language so that you can read a diamond grading report with confidence and know what each grade really means.
Gemstones
The 4Cs, the great coloured stones and the largest diamond ever found.
Every gemstone is a small piece of geology with a story attached. In this rubric we make the 4Cs of diamonds visible, introduce sapphire, ruby and emerald with their famous sources, and follow the Cullinan from a South African mine to the British Crown Jewels.
Sapphire, ruby, emerald: the coloured stones with royal pedigree
The three great coloured gemstones share a long royal history. What they are made of, where the finest come from, what affects their value and which famous jewels made them stars.
The Cullinan: the story of the largest gem diamond ever found
Found in South Africa in 1905, given to Edward VII in 1907 and cut in Amsterdam in 1908: how the largest gem diamond ever found became part of the Crown Jewels.
Try it yourself
Diamond 4C Studio
See how carat, colour, clarity and cut change a diamond, with true to scale size.
Continue the tour
More rubrics
- JewelleryTiaras, pearls and signet rings: the pieces that carry a family’s history.
- WatchesComplications, etiquette and the long road from pocket to wrist.
- CoutureHaute couture, royal wedding dresses and the craft of bespoke tailoring.
- CollectiblesWatches, royal memorabilia and the paper trail that makes objects valuable.
- Luxury BrandsHeritage houses, royal warrants and the codes of quiet luxury.
- Royal FamiliesDynasties, coronations and the jewels that pass between generations.
- AuctionsHow sales work, record results and a calm checklist for bidders.
- ArtRoyal collections, attribution and how to start collecting.
- AteliersGoldsmiths, hallmarks and the watchmaker’s bench.