Cut of a Diamond

‘Cut’ is considered to be the most important characteristic of a diamond. It refers to the angles and proportions created when a rough diamond is transformed by a diamond cutter into its final polished state.

The cut grade is a measure of how well light is reflected within a diamond, and is what will produce what we call ‘sparkle’.

When a diamond is cut well, light is returned out of the top of the stone, whereas if it is cut poorly, light leaks out the bottom of the stone producing less ‘sparkle’.

Diamond Cut Grade List

Excellent / Ideal Cut

Reflects nearly all light that enters the diamond. Diamonds with an Excellent cut grade are very rare and command more premium prices. If you would like an Excellent cut stone, please contact us.

Very Good Cut

Reflects nearly as much light as the excellent cut, but for a lower price. The most popular choice of cut grade and the cut grade that Purely Diamonds offers as standard for all round diamonds.

Good Cut

Reflects most of the light that enters the diamond. Considerably less expensive than a very good cut.

Fair Cut

Not a cut we would recommend, a fair cut will not be as brilliant as a good cut.

Poor Cut

Diamonds that are generally so poorly cut they lose most of the light out of the bottom and sides of the stone.

We use ‘Very Good’ cut graded round diamonds as standard.  The untrained eye will often not detect the difference between a Very Good or an Excellent cut stone. Diamonds with a cut grade of Good or Very Good, represent an excellent combination of value and sparkle, particularly Very Good cut diamonds which reflect nearly as much light as an Excellent cut stone but for a lower price.

Be wary of companies who sell cut grades such as “Super Ideal,” “Signature Ideal,” and others. These ‘branded’ cut grades are not part of the internationally recognised GIA grading standard, which only uses Excellent, Very Good, Good, Fair and Poor. 

Non-Round (Fancy Shape) Diamonds

(Princess, Emerald, Oval, Marquise, Radiant, Asscher, Pear, Heart, Baguette)

Fancy Cut Diamonds are any and every shape of stone other than a Round diamond, such as Marquise, Princess, Emerald, Oval etc.

Fancy Cut Diamonds do not have a cut grading.

Fancy shapes have a Polish and a Symmetry grading, rather than an overall ‘cut’ grading.

At Purely Diamonds we always use fancy shaped diamonds with polish and symmetry grades of at least ‘Good’, usually ‘Very Good’.  There is no internationally accepted system for visually evaluating the appearance of fancy-cut diamonds in order to give a diamond a ‘cut grade’.

This is because Fancy Shapes have endless variations of Widths, Lengths, Depths, and Proportions – every one could be a slightly different shape, whereas with round diamonds they are always symmetrical and round in shape.