1.03 Carat marquise diamond E ColorVS1 Clarity Janes Allen1.03 Carat marquise diamond E ColorVS1 Clarity Janes Allen

James Allen Diamond Cut Guide: Overview, Grades, Quality and Price

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HomeDiamond AdviceJames Allen Diamond Cut Guide: Overview, Grades, Quality and Price

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Diamond Cuts

When it comes to sparkle, a diamond's cut is the deciding factor. Cut describes how a diamond's surface has been cut into lots of tiny facets. The size and orientation of these facets affect how light will pass through the diamond. Poorly cut diamonds won't reflect as much light as well-cut diamonds, making them look dark, dull, and lackluster. In a well-cut diamond, almost all of the light is reflected through the top, giving it the characteristic brilliant sparkle. 

Almost all of the light that enters an Ideal cut diamond will reflect out of the top of the diamond, giving it brilliance, sparkle, and fire. From James Allen.

Each gemological lab grades diamond-cut differently. Cut grades are based on an assessment of a diamond's measurements, polish, and symmetry. The most well-known lab is the Gemological Institute of America (GIA), which grades cut as excellent, very good, good, fair, and poor. James Allen sells diamonds graded by the GIA, as well as the International Gemological Institute (IGI) and the American Gem Society (AGS). 

IGI cut grades are ideal, excellent, very good, good, and fair. The AGS grades diamond cut on a scale of 0-10. A grade of 0-1 is excellent, 2 is very good, 3-4 is good, 5-7 is fair and 8-10 is poor. 

Diamond-Cut and Diamond Shape

This James Allen 1.03 carat E color VS1 clarity marquise diamond is well-cut. It has excellent symmetry and polish, and a length-to-width ratio of 1.91.

Although cut is one of the most important diamond qualities, the GIA only grades cut for three diamond shapes: round, princess, and cushion. Why? It's difficult to grade the cut of fancy-shaped diamonds, like emerald, radiant and oval, because their proportions and cut styles are so different from the classic round shapes. 

Instead of looking at cut, you can evaluate fancy-shaped diamonds by polish, symmetry, and measurements. Polish describes how smooth a diamond's surface is-the smoother the surface, the better the diamond will perform. Look for fancy-shaped diamonds with an excellent or very good polish. 

The length-to-width ratio is another way to evaluate the cut of fancy-shaped diamonds, particularly oval, pear, marquise, and heart shapes. Each diamond shape has a range of ideal length-to-width ratios-look at the detailed information James Allen provides about each diamond's measurement to see if the diamond is within the ideal range. Carefully examine the detailed 360° images of each diamond to make sure the bowtie effect is not too pronounced.  

For square or rectangular diamonds, like radiant, asscher, and emerald, symmetry is a good indicator of cut quality. Look for diamonds with parallel sides and avoid diamonds with narrow or uneven corners. 

James Allen Diamond Cuts

James Allen sells round, princess, and cushion diamonds with four cut grades: good, very good, ideal, and True Hearts. True Hearts diamonds are only sold by James Allen and have superior quality, with perfect internal symmetry and proportions. The cut grading system is the same for natural diamonds and lab-grown diamonds.

Evaluating a James Allen diamond's cut online is easy. You can for the specific cut you want in their huge collection of loose diamonds. Each diamond includes a lab report, so you'll know exactly what you're getting. 

0.72 Carat Princess Diamond F Color VVS2 Clarity Good Cut © James Allen
0.80 Carat Princess Diamond F Color VVS2 Clarity Ideal Cut © James Allen

Shopping for diamonds on the James Allen website is a breeze. Each diamond's color, clarity, and cut grade are right there in the search results. On the left, a 0.72 carat F color VVS2 good cut princess diamond for $1,870. On the right, a 0.80 carat F color VVS2 ideal cut princess diamond for $2,420. Ideal cut diamonds come at a premium, but with more sparkle and brilliance. 

True Heart Diamonds

James Allen True Heartsdiamonds are the premier selection of ideal/excellent cut diamonds. Fewer than 1% of the diamonds in the world qualify as True Hearts diamonds. True Hearts diamonds have perfect internal symmetry and proportions and are the most brilliant diamonds of all.  

Round True Hearts diamonds are "hearts and arrows" diamonds, showing a stunning pattern of hearts and arrows when viewed from above. This unique pattern can only be achieved by a highly-skilled diamond cutter. 

This James Allen 1.19 carat round True Hearts diamond exhibits a beautiful hearts and arrows pattern, shown in red (arrows in the middle and hearts on the far right).

Ideal Cut Diamonds

James Allen ideal cut diamonds are typically ranked excellent by the GIA, excellent/ideal by the IGI and 0-1/excellent by the AGS. Ideal cut diamonds are cut so that the proportions and angles are perfect. They also have excellent symmetry and polish ratings. Almost all of the light that enters an ideal cut diamond will be reflected out of the top, so they will have maximum sparkle and brilliance.  

This James Allen Ideal cut 1.04 carat E color VVS1 clarity round diamond has excellent cut, polish, and symmetry-the coveted Triple X grade.

Very Good Cut Diamonds

James Allen very good cut diamonds are ranked very good by the GIA and IGI and 2/very good by the AGS. Very good cut diamonds are a step below ideal cut but have very similar properties. Only a small portion of light is reflected out the bottom of very good diamonds, so they are almost as sparkly as ideal cut diamonds. Very good cut diamonds are sold at a slightly lower price point than ideal diamonds, which can help with the cost if you want a larger diamond, like 1.25 or 1.5 carats. 

This James Allen 0.8 carat D color VVS2 clarity very good cut pear diamond is almost as sparkly as an ideal cut diamond.

Good Cut Diamonds

James Allen good cut diamonds are typically ranked good by the GIA and IGI and 3-4 by the AGS.  A good cut diamond is a great option if you are on a budget but want a classic round, princess, or cushion diamond. These quality diamonds still have beauty and sparkle but are more affordable.  

Buying James Allen Diamonds Online

Always look at the diamond's measurements before buying! Both of these 0.91 carat round James Allen diamonds have a good cut rating but will perform differently in light. The diamond on the left has a larger table (the flat facet on the top of the diamond) and a higher table percentage than the diamond on the right. Diamonds with a table percentage outside the ideal range may appear dull. 

Buying diamonds online is easy with James Allen. You can search their collection of over 500,000 loose diamonds to find the perfect stone for your engagement ring. 

If you're looking for a round, princess, or cushion-shaped diamond, you can narrow down your search by cut grade. Fancy-shaped diamonds aren't graded by cut, but you can evaluate their symmetry and polish to get an idea of the cut quality. Every James Allen diamond has detailed information about symmetry, polish, and diamond measurements, so you'll know exactly what you're getting. 

Diamond prices vary based on cut grade, with the True Hearts cuts commanding the highest price. For a 1 carat F color VVS2 round diamond, a True Hearts branded diamond will cost around $9,800. The same diamond with a cut grade of ideal will cost much less, around $6,040. Very good and good cut round diamonds are only a few hundred dollars less. Unless you want a near-perfect diamond, ideal or very good cuts are excellent options. 

The cut is the most important characteristic of a diamond. A diamond with the right cut will be truly stunning. 

Courtney Beck Antolik

Courtney Beck Antolik is a geologist and science writer based in Denver, CO. She received a B.S. (2010) in Geology from Texas A&M University and an M.S. (2013) in Geological Sciences from the University of North Carolina at Chapel Hill. Courtney’s experience with minerals includes a zircon geochronology project and a semester teaching mineralogy labs. Her favorite mineral is beryl, but diamond is a close second.

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