Clarity barely affects sparkle – cut does nearly all of it. What brilliance, fire and scintillation really come from, and the one exception.

Flawless is the top grade. Here is what FL, IF, VVS1 and VVS2 really mean, and when paying for the top of the scale is worth it.

The full FL to I3 clarity scale in plain English, what the numbers really mean, and which grade to buy for each diamond shape and size.

What diamond colour and clarity actually measure, how laboratories rate them, and how to read the two grades together.

Cut beats both, but once that is settled the answer depends on your shape and metal. A clear decision table, including round diamonds.

G colour and VS2 clarity suits most rings. How to adjust that for your shape, metal and carat weight, with three worked examples.

Excellent cut and VS2 clarity is the combination we recommend most. Both scales explained, plus where the exceptions are.

Clarity enhanced means treated: fracture filling or laser drilling. What each does, why filling is not permanent, and what it costs you.

Flawless is the most expensive diamond clarity grade. The full FL to I3 scale explained, and whether it is worth paying for.

How melee diamonds are cut, from rough crystal to sieved, matched stone: sawing, bruting, brillianteering and hand setting explained.