This guide should help you understand diamond cut quality and make an informed decision when purchasing an engagement ring. Knowing the diamond’s cut grade, symmetry and polish, depth, table percentage, and sparkle can give you a good indication of its overall beauty. With these tips in mind, you can be sure to find the diamond of your dreams.

1: Understanding Diamond Cut Quality

When buying an engagement ring, one of the most important factors to consider is the diamond’s cut quality. Diamonds are formed deep within Earth’s surface and, as they travel to the surface, each diamond reflects light in its own unique way which is what gives them their beauty.  First, let’s define what we mean by diamond cut quality. Diamond cut quality refers to the precision and skill with which a diamond is cut and polished. A well-cut diamond will have facets that are symmetrical, evenly spaced, and precisely angled. These precise angles and symmetry allow light to enter the diamond, reflect off its facets, and return to the viewer’s eye as a dazzling display of sparkle and fire. A diamond’s cut quality refers to how well a diamond’s facets interact with light – it affects a diamond’s overall brightness, fire, and scintillation. The Gemological Institute of America (GIA) uses a scale from Excellent to Poor to grade diamond cut quality. In order to evaluate diamond cut quality, look for a diamond with a GIA cut grade of Excellent or Very Good. Pay attention to the diamond’s symmetry and polish; these should also rate an Excellent or Very Good. Consider proportions such as depth and table percentage – both are important aspects in assessing diamond cut quality. Lastly, observe the diamond in different lighting conditions to get a sense of its overall sparkle. n contrast, a poorly cut diamond will have uneven and misaligned facets that are either too shallow or deep. This causes the light to escape from the diamond instead of reflecting it back which results in its lackluster appearance.

The Diamond cut is the quality that breathes life into the stone. The allure and beauty come from the diamond’s fire, sparkle and brilliance. By far the most important C in the 4 C’s of Diamonds. These are the major components that attribute to the Cut grade.

diamond cut chart

4 C's of Diamondsvia GIAThe major components, from top to bottom, are the crown, girdle and pavilion. A round brilliant cut diamond has 57 or 58 facets, the 58th being a tiny flat facet at the bottom of the pavilion that’s known as the culet. The large, flat facet on the top is the table. The proportions of a diamond refer to the relationships between table size, crown angle and pavilion depth. It is important to note that a wide range of proportion combinations are possible, and these ultimately affect the stone’s interaction with light and how attractive the diamond is to the person viewing it.”

An important wording to point out ” wide range of proportion combinations are possible”.  Sometimes the most ideal numbers don’t add up once you add up all the angles and attributes. Each stone is different.  This especially holds true to Fancy shapes(anything other than a round diamond).

Huge Tip:

Round diamonds are the easiest to buy regarding CUT.  Gia offers a cut grade only for Round Diamonds.  All Other Shapes like Princess, Emerald Cushion don’t have an official cut grade.  You have to evaluate the stone by eye and various elements such as table and depth percentages.  If this is confusing, please contact me here so I can guide you.     

James Allen, Blue NileandBrian Gavinall have their signature line of cuts.  If you are buying round you may not need to go there, however for any shape such as Princess, Cushion, etc.  It’s not a bad idea to look.  Pricing is fair for the quality.

Blue Nile has Their Astor Line.  They have brilliant Princess and Cushion cuts.  If you are shopping for those its worth taking a look here.

Brain Gavin has its Signature Diamonds Cut Linewhich often come with a AGS Diamond Certificate.   Its the only certificate focusing on light performance of a diamond.  Brian Gavin is a master diamond cutter that is known for the best cuts.  I Highly recommend a Fancy Shape Diamond(Princess,Cushion, Emerald, Oval ETC) to have a AGS Certificate.

James Allendoesn’t have a signature series but that doesn’t matter.  In there filters for diamond search, you can put AGS diamond certificate.  This means any fancy shape diamond with a grade of  O (ideal) means its a brilliant light dazzling diamond.

Your Fancy Shape Diamond(any diamond other than round)  wont display a cut grade, you must click on AGS diamond certificate picture and read.  

See sample below

4 C's of Diamonds

A signature series is nice because it takes the guess work out of it.  But not always necessary to find a beautiful diamond.  In the end you must gauge price with attributes.   I give my clients options for the top 3 diamond providers so they can compare offerings.  Each company has their strengths. 


2: How to Evaluate Diamond Cut Quality

The Gemological Institute of America (GIA) uses a scale from Excellent to Poor to grade diamond cut quality. An “Excellent” cut grade means that the diamond has been cut to the highest standards, and it will have the most brilliant sparkle and fire. A “Very Good” cut grade means that the diamond has been cut to very high standards, and it will have excellent sparkle and fire. When a diamond is given a “Good” cut grade, it indicates that its standards meet the criteria for good sparkle and fire. However, if the stone has been classified as “Fair”, this implies that its light performance may not be up to par. On the other hand, when labeled as a “Poor” cut grade, it’s an indication of inadequate precision in cutting which will ultimately result in lackluster sparkles and glimmers, and it will have very poor sparkle and fire.

Now that we are familiar with what diamond cut quality is and how it’s graded, let us delve into why this knowledge matters. A well-cut diamond will appear larger and have a superior sparkle than its poorly cut counterparts of the same carat weight. Not only that, but you’ll also be able to relish in the beauty of your gemstone for years to come – plus benefit from an exceptional value!

When evaluating diamond cut quality, there are several elements to take note of. First and foremost, always search for a diamond with superb GIA ratings such as Excellent or Very Good – these diamonds have been expertly crafted according to the best standards possible so that it will exude blazing radiance and fire. Additionally, pay attention to its symmetry and polish too; a well-cut gemstone should feature consistent angles between all its facets plus possess an impeccable mirror-like finish.

Consider the diamond’s proportions, including the depth and table percentage. A well-cut diamond will have a depth percentage between 59% and 62%, and a table percentage between 53% and 57%. These proportions will allow for the optimal balance of light reflection and dispersion.


Diamond ShapeIdeal Depth & Table PercentageClick link To View Sample
RoundTable: 53-59% Depth: 59-63%
Click Here to view ideal Round
PrincessTable: 67-73% Depth: 64-72%
Click Here to view Ideal Princess
OvalTable: 53-63% Depth: 58-63%
Click Here to view Ideal Oval
PearTable: 53-63% Depth: 55-62%
Click Here to view Ideal Pear
CushionTable: 61-67% Depth: 61-67%
Click Here to view Ideal Cushion
EmeraldTable: 61-69% Depth: 61-67%
Click to view Ideal Emerald
RadiantTable: 61-69% Depth: 61-70%
Click to view Ideal Radiant
AsscherTable: 61-69% Depth: 61-67%
Click Here to view ideal Asscher

Below is my prefiltered ideal cut setting for all diamond shapes. Click on the appropriate tab to discover filtered diamonds with my filtered ideal settings 


In conclusion, when shopping for diamonds, it is important to pay attention to diamond clarity. Knowing the various diamond clarity grades can help one make an informed decision about which diamond is best for them, ensuring that they are getting the most beautiful diamond for their budget. With such knowledge in hand, anyone can purchase a truly exquisite diamond that sparkles as brightly as a star from heaven!

Recommended Places To Buy

For me to recommend any business, they must meet certain criteria. They must prove valuable to my clients in regards to How to buy a diamond savings and selection | EXPECT 20%-40% LOWER PRICES THAN TRADITIONAL JEWELERS |, time doing business(legitimacy), reputation, and return policy.

James Allen Logo

James Allen  has the highest volume in diamond sales in the web and now have 500,000 diamonds in their inventory.  They have industry leading diamond viewing technology.  The ability to see your diamond more clearly than in a physical retail store is a massive plus for you. JA has incredible costumer service and have a massive Lab created diamond consisting of HPHT diamonds in their inventory.

They have free shipping domestic + international – free ring resizing –  no questions asked money back return 30 days  – provides insurance appraisals –  lifetime warranty


Blue nile logo

Blue Nile was the original online giant that opened in 1999! They have the industry-leading largest available exclusive online inventory.  They have incredible prices and their images are catching up to James Allen.

No questions asked money back 30 day guarantee – Free shipping – Free ring sizing – Provide insurance appraisals –  Lifetime warranty – 100% future credit towards upgrades


Feel free to reach out and send me a message. Do you want buying advice on How to buy a diamond or have you found a stone you wish for me to evaluate. Feel free to drop me a line and say hello. Advice is free.


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