Engagement Rings Education

What are the Four Cs?



The cut of a diamond determines its sparkle, or brilliance. Out of the 4 Cs, the cut is the most important influencer of how beautiful a diamond is. A poor or even average cut can make a diamond look dull and lifeless. We only sell the top grades of cuts for all our diamonds.

Diamond Cut Grades


Ideal Cut

An Ideal cut is one of the rarest. It is used as the benchmark on which to measure all other diamonds. Almost all light that enters it is reflected and it has excellent symmetry and polish ratings.

Excellent Cut

An Excellent cut is the highest grade that GIA awards and includes diamonds which are cut within very fine tolerances of the ideal cut. Excellent cut diamonds have the highest levels of performance with superb brilliance, fire and scintillation.

Very Good Cut

A Very Good cut is regarded as a wise choice and a sound investment. The cut allows for light to be reflected, and spending more on a larger carat weight offers a more appealing diamond.

Good Cut

Diamonds classified as a Good cut are still pretty to look at and reflect light however they do not perform in the same way as Very Good cut or Excellent cut diamonds. Good cut diamonds do not meet Thomas quality standards and are not stocked by us.

Fair Cut

Fair cut diamonds have imperfections that result in dull diamonds. They are usually cut too shallow or too deep and don’t have good light reflection. Thomas doesn’t stock these diamonds as they are not worth using in quality pieces such as engagement rings.

Poor Cut

Poor cut diamonds have many imperfections that result in very dull diamonds. They have been cut too shallow or too deep and don’t reflect light very well. Thomas does not stock these diamonds.

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