Diamond Buying School is reader-supported. Here's how it works.

Diamond Cut

by David Weliver

A diamond’s cut is arguably the most important of the 4 C’s. The cut refers to how a diamond reflects light, which is what gives the stone its brilliance.

Diamond Cut

A well-cut diamond cut will reflect light perfectly. This will make a diamond shine in any light and seem to radiate fire under the intense lights of a jewelery store.

A lesser-quality cut, on the other hand, will “leak” light. This means that when light goes into the top of the stone, instead of being reflected back upwards, the light will escape out the sides and bottom of the stone. These diamonds may still look great in the jewelery store, but won’t shine as brightly in other light.

There are different grading systems for a diamond’s cut, but these are the most common ones you’ll see:

Depending on the retailer, you may see other cuts that are claimed to be better than ideal. When shopping for a loose diamond or engagement ring, you most likely won’t come across a diamond cut grade below “fair”.

What Diamond Cut Grade Should You Buy?

Choosing your perfect diamond comes down to the perfect mix of grades and characteristics for your budget. We might al like a 2.5 carat ideal cut diamond, but most of us couldn’t afford it.

When a diamond is cut, the gemcutter must make a decision to make either all of the recommended cuts to produce an ideal cut diamond, sacrificing material from the rough diamond. Alternately, he can make slightly less “perfect” cuts to create a larger finished stone. The results are variation in the diamond’s cut grade.

To help you choose the perfect diamond cut, we’ve outlined more about what you can expect from each. You can also click to view each example image in a 360 viewer on James Allen, one of our recommended jewelers.

Ideal Cut
Ideal cuts are only found in round diamonds. Vendors may have other grades such as “signature ideal” to describe diamonds in other shapes that have excellent cuts. Ideal cut diamonds have been precision cut to maximize the fire shown by the diamond when light hits it. This means you’re getting one of the best diamonds out there, but expect to pay a premium for it. View 360° example.

Very Good Cut
JA_cut_verygood_SKU173787Diamonds that are graded with a very good cut will still look brilliant. Very good diamonds will reflect most light. Typically, these diamonds are created because the gemologists have cut in “less than perfect” proportions because they wanted to maximize the diamond’s size. Most very good cut diamonds make excellent stones for engagement rings or other solitaire settings. View 360° example.

Good Cut
JA_cut_good_SKU240014Good cut diamonds offer an excellent value while still reflecting a lot of light and creating a brilliant appearance. If you’re after a larger stone, you may want to choose a good cut diamond. View 360° example.

Fair Cut
In general, avoid diamonds that are given a fair cut grading. These stones have been cut to be as large as possible, but won’t be nearly as brilliant as stones with higher cut grades.


Recommended Jewelers

James Allen

James Allen logo

James Allen is the most competitive diamond vendor with more than 150,000 loose diamonds in inventory. They have been a leader in selling diamonds online and pioneered 3D imaging so you can see the exact diamond you're buying in exquisite detail. You'll find it hard to beat James Allen in terms of price or selection. Read our James Allen review.

Shop James Allen »


Whiteflash logo

Whiteflash is the home of "A Cut Above" diamonds which are among the best quality round- and princess-cut diamonds in the world. With superior diamond photographs and videos, Whiteflash's diamonds seem to come to life -- even online. Read our Whiteflash review.

Shop Whiteflash »

Brilliant Earth

Brilliant Earth logo

Brilliant Earth is the global leader in ethically-sourced jewelry. Brilliant Earth goes above and beyond existing standards to offer “Beyond Conflict Free Diamonds” that they select for their ethical and environmentally-responsible origins. With over 120,000 diamonds in inventory, you can be sure to find your perfect diamond and feel good knowing it was responsibly-sourced. Read our Brilliant Earth review.

Shop Brilliant Earth »

Blue Nile

Blue Nile logo

Blue Nile is the world's largest online jeweler. Their reputation for quality and customer service is unparalleled in the industry. Blue Nile offers free shipping, a 30-day return policy and satisfaction guarantee. Read our Blue Nile review.

Shop Blue Nile »