Every diamond is graded on four qualities — Cut, Colour, Clarity and Carat. Together they explain almost every price difference you'll ever see, and knowing them helps you buy the diamond that matters most to you rather than the one on a marketing poster.
Cut
Cut is the single most important C. It measures how well a diamond's facets return light to your eye. A well-cut stone looks brighter and larger than a poorly cut stone of the same weight. Aim for Excellent or Ideal cut on round brilliants; on fancy shapes, we hand-pick each stone in person.
Colour
Graded D (colourless) through Z (light yellow). D–F are considered colourless, G–J near-colourless. For most settings we recommend G or H — visually white to the eye, meaningfully better value than D.
Clarity
Graded from Flawless (FL) down to Included (I3). Most inclusions are invisible without a loupe. VS1–VS2 and SI1 with a good spread of inclusions offer the best value for money.
Carat
Carat is weight, not size. A 1.00ct round is roughly 6.5mm across; a 1.50ct is around 7.4mm. Buying just under a whole-carat "magic size" (0.90ct instead of 1.00ct) can save 15–25% for a visually identical stone.
How Altin uses the 4Cs
We start with your budget and the look you want on the finger, then work backwards through the 4Cs to find the best diamond within that envelope — never the other way around.