Cut
Cut grades how well a diamond’s facets return light. It has the biggest effect on sparkle, so it is the last place to economise.
Colour
Graded from D (colourless) to Z. G–H look colourless once set, especially in white metal, and offer better value than D–F.
Clarity
Measures inclusions under 10× magnification. VS1–VS2 stones are eye-clean; SI1 can be eye-clean with careful selection.
Carat
A unit of weight (0.2 g), not size. Elongated shapes such as oval and pear look larger per carat than round.
