The 4 C's of Diamonds

The 4 C's are decisive criteria for the value assessment of a diamond:

Carat (weight), Color, Clarity and Cut of a diamond determine its value. The heavier, whiter and purer a diamond is and the more perfect its cut, the more valuable it is.

Carat (Weight)

1 Carat = 0,20 g

The weight of a diamond can be estimated relatively easily by measuring its diameter:

4,10 mm = approx. 0,25 ct.
5,20 mm = approx. 0,50 ct.
5,90 mm = approx. 0,75 ct.
6,50 mm = approx. 1,00 ct.


The colour of a diamond is divided into 6 groups:

  • Highly fine white (D-E River)
  • Fine white (F-G Top Wesselton)
  • White (H Wesselton)
  • Slightly tinted white (I-J Top Crystal-Crystal)
  • Tinted white (K-L Top Cape – Cape)
  • Tinted (M-Z Cape-Yellow)


The clarity of a diamond/brilliant is determined by the type and amount of natural inclusions. The following international grading scale is used:

  • IF = Loupe clean
  • VVS = Very, very small inclusions, hardly visible 10 times magnified
  • VS = Very small inclusions, relatively well visible 10 times magnified
  • SI = Small inclusions, only visible 10 times magnified – still eye clean
  • P = larger inclusions, visible with the naked eye


The cut is another important criterion for brilliance and fire of a diamond/brilliant. The better the cut, the better are fire and brilliance of the diamond. The quality of the cut is referred to as:

  • Excellent
  • Very good
  • Good
  • Fair
  • Poor

In our price lists you can find the diamonds/brilliants with the properties that are the most common on the market.

Upon request we can provide you with information on the price of diamonds/brilliants with different properties.

At InLumen all diamonds/brilliants are certified. The certificate is the ID of a diamond. It contains all important properties to be able to identify the diamond beyond doubt.

The certificates are issued by renowned international and national laboratories such as GIA, IGI, HRD, DPL or DGPL and are delivered together with the piece of jewellery.


If you have any questions about our offers, feel free to contact us at any time, without obligation.

Are you looking for...

a particular diamond or a particular piece of jewellery?

If you are looking for diamonds or jewellery that we are not offering, please let us know. We will try to find your desired diamond or jewellery to submit you an offer.

You would like to...

sell a diamond or a particular piece of jewellery?

If you would like us to sell your diamond or jewellery for you, or to accept it in payment, feel free to contact us and to use our services and sales channels. Please use the contact form for buying requests and sales first and provide as much information as possible. In this way we are able to do research in advance and to answer your requests competently.