Diamond cut

Cut is the only one of the 4C's that measures how a diamond performs. It is also the one buyers most often underweight, and the one with the largest effect on both appearance and price.

What cut actually measures

Cut grading assesses three things: proportions (how the stone's angles relate to one another), symmetry (whether those angles match precisely), and polish (the smoothness of the facet surfaces). Together these determine how much light a diamond returns to the eye instead of leaking out the bottom or escaping through the sides.

The grades

• Excellent — maximum light return and brilliance. The top grade.
• Very Good — very strong light return with minor precision differences. Excellent value.
• Good — noticeably less bright than the grades above.
• Fair — dim, with visible leakage or a dark center.
• Poor — light leaks substantially. We do not sell these.

Why cut is the most important

A well-cut smaller stone looks better than a poorly-cut larger one. Cut controls brilliance and apparent size at the same time. If you are choosing where to compromise on the 4C's, cut should be the last one you give up, not the first.

How much is the cut grade worth

Within a fixed carat, color, and clarity, moving from Good to Excellent cut can change price substantially, sometimes by 30% or more. That is the largest single multiplier in the 4C's. Very Good delivers most of the visual benefit of Excellent at a meaningfully lower price, which makes it our most common recommendation.

Terms you may see

Windowing is when a stone becomes see-through in the center from certain angles. Cladding is a surface haze that mutes brilliance without changing the grade. Bow-tie effect is a dark bow-tie across the center of some fancy shapes, most often in oval and pear cuts. Ask about all three when buying a fancy shape.

Frequently asked questions

Is Excellent cut always the right choice?

Usually. Very Good is often the better value because the visual difference is subtle while the price difference is not. For fancy shapes, the grading is more subjective, so judging the specific stone matters more than the letter.

Can a diamond be cut well if it is heavily included?

Yes, but it will look duller regardless of grade. Clarity and cut interact: a poorly cut stone hides its own inclusions, and a well cut stone makes inclusions more visible. See clarity.