- Cut: The proportion, finish, symmetry and polish of the diamond. Check a stone in natural light as far as possible because showroom lights enhance natural brilliance.
- Carat: The unit of weight for the diamond is carat, broken into 100 centimes, roughly equal to 0.20 gm. Value per carat increases with size.
- Clarity: The clearness or purity of a diamond. Naturally occurring blemishes, either internal or external, reduce the value. The best are obviously flawless or F, followed by VVS1 and VVS2. Check your certificate.
- Colour: Range from colourless to yellow, about 23 types. Fancy colours like intense yellow to brown, blue, green, pink and red are rare and therefore more valuable.