Diamond Cut Chart: Good vs Very Good vs Excellent Cut

Note: Most prices, product details, or comparisons mentioned in this article are based on information available from our trusted partner we frequently reference: Blue Nile.
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Note: Most prices, product details, or comparisons mentioned in this article are based on information available from our trusted partner we frequently reference: Blue Nile. We may earn a commission when you purchase through our affiliate links, at no extra cost to you. This helps support our work and allows us to continue providing unbiased, expert diamond advice.

Summary in a few lines:

Cut is the one grade of the 4Cs you can read across a room, and only 3-5% of the diamonds cut worldwide earn the top Excellent grade.
GIA grades cut on 5 levels: Poor, Fair, Good, Very Good and Excellent. Buy Excellent (listed as Ideal by most retailers), and NEVER go below Very Good.
Good cut is not good. On a 1 carat, H color, VS2 clarity round, the Good range we recorded ran $3000 to $3700 while Very Good ran $3500 to $4700, a modest premium for a visible jump in light return.
Excellent and Ideal describe the same tier on most listings: AGS calls its top grade Ideal (AGS 0), GIA calls it Excellent, and GIA defines nothing above Excellent.
If you’ve mistakenly equated ‘diamond cut’ with ‘shape,’ feel free to check our guide to the most popular diamond shapes.

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Table of Contents

What is Diamond Cut?

Diamond cut is the set of proportions, angles and finish a cutter gives a rough stone, plus how well the finished facets hand light back to your eye. It is not the shape. Two stones can be round brilliants of identical weight, and one will look alive while the other looks like glass.

Ever noticed how some diamonds dazzle brilliantly while others don’t?

That’s what exactly is the diamond cut.

On a grading report, cut bundles three separate things together: the proportions of the stone, the symmetry of its facets, and the quality of its polish. GIA compresses all of that into a single word.

Shape is the outline (round, oval, emerald). Cut is the light performance inside that outline, and it is graded, while shape never is.

Put simply, you are not buying a rock, you are buying the way that rock behaves under a light bulb.

How Does Cut Affect Brilliance and Light Reflection?

Cut decides how much light enters the crown, bounces between the facets, and returns through the table to your eye. Correct angles send nearly all of it back as brilliance, fire and scintillation. Wrong angles let light leak out of the pavilion or the bottom, so the stone reads flat, dark or watery.

The cut of a diamond is an artful science, determining its brilliance and sparkle. It involves a harmonious balance of the diamond’s proportions, including its dimensions, surface polish, depth, and symmetry.

These elements combined dictate the diamond’s ability to reflect light. The more harmonious these elements, the more stunning the diamond’s reflection and sparkle.

Among the 4Cs of diamond quality, the cut reigns supreme. It affects what your eye sees before clarity or color get a vote.

A slight change in clarity or color might go unnoticed. But a drop from an ‘Ideal’ to a ‘Good’ cut grade? That’s something you’ll see right away.

Want to test that yourself instead of taking our word for it? Feel free to open the round diamond search on Blue Nile, lock color at H, clarity at VS2 and weight at 1 carat, then flip the cut filter from Good to Very Good to Ideal and watch the 360-degree videos of each.

Fact: It has been proven by gem professionals that no two diamond stones are identical. You can never find two stones with the same exact characteristics, although they might look the same to a layman’s eye.

Shallow vs Deep vs Ideal Cut

An ideal-cut stone passes light from facet to facet and sends it back out through the table. A stone cut too deep loses light through the far side of the pavilion, so it looks dark in the middle. A shallow stone looks wider from above, but light escapes through the bottom before it can reflect.

Shallow stones are cut that way for a reason: they spread the weight over a bigger face-up area, so they measure larger for the same carat. That is a selling point, not a quality point.

What makes a diamond notable isn’t its size, but how the light “dances” when the hand moves, so don’t chase a larger stone before you’ve guaranteed an excellent cut.

Remember this: when a diamond is cut too deep, some light escapes through the opposite side of the stone. If the cut is too shallow, light escapes through the bottom before it ever gets the chance to be reflected.

The numbers behind all of this are the table and depth percentages printed on every report; if you want the ranges that actually work per shape, read our guide to the best diamond table and depth percentages.

Diamond Cut Grade Chart: The Five GIA Grades

GIA grades cut on five levels: Poor, Fair, Good, Very Good and Excellent. Each level is a verdict on light return, built from proportions, symmetry and polish together. Excellent sits at the top of the GIA scale, and anything below Very Good is a compromise you will see with your own eyes, not only on paper.

Just as there are charts for clarity and color, with the diamond clarity chart indicating purity and the diamond color chart showing how colorless a stone is, cut has its own scale, and the GIA cut grading chart is the one the market runs on.

Tip: some retailers offer a ‘Super Ideal’ tier above Excellent; it is a house grade, NOT a grade defined by GIA, so you will never see it printed on a GIA report.

Let’s take a closer look at each of the five grades.

1. Poor

These diamonds are the lowest in quality, lacking both brilliance and fire. Poorly proportioned, they reflect little light and look dull in almost any lighting.

Typically they are cut far too deep or far too shallow, so light escapes through the sides or the bottom.

Reputable online diamond stores (like Blue Nile’s certified diamond inventory) do NOT stock poor cut diamonds at all, so the grade is mostly a local-counter problem.

2. Fair

Not the worst, but fair-cut diamonds have limited sparkle because of a subpar cut. They show some life and still miss most of their potential light return.

Like Poor, this grade is very unlikely to appear on a reputable online store. If you meet one in a local shop, always see and verify the diamond certificate before you go anywhere near a payment.

Tip: even on a very tight budget, we would never recommend this grade. Consider a lab-grown diamond at a better cut grade instead, and just NEVER get a fair-cut stone.

3. Good

Good cut diamonds are partially well cut. They keep a reasonable face-up look, and they do not return all the light entering them, yet they are still considered not that cheap.

You would think good is actually good, but in diamonds, good cut is really bad. The name flatters the stone.

You can find good cut diamonds on almost all online merchants (although very little options). If you want our professional opinion, we wouldn’t recommend this grade.

4. Very Good

These stones are cut to produce a lot of sparkle, close to the maximum the rough allowed. They return nearly all the light that enters, striking a balance between quality and cost.

We consider this grade to be, how can we say that, the most budget-friendly one of all! (it’s still expensive though).

We always push for Excellent even at a lower carat, and plenty of buyers land on Very Good because it costs less. That is a defensible choice; Good is not.

5. Excellent | Ideal

If you’re asking: what is the best diamond cut out there?

The Excellent cut, no question!

These stones are crafted to reach maximum brilliance and fire, returning virtually all the light that enters. Always seek an ideal cut even if it means getting a lower carat.

Ideal and Excellent are used interchangeably by online merchants. On certificates, AGS treats Ideal (AGS 0) as its top grade, while GIA defines nothing above Excellent.

When proportions, symmetry and polish all land at the top of the scale together, the report reads GIA Excellent three times over; that combination is covered in our guide to triple excellent diamonds (GIA XXX).

Fact: only 3-5% of diamonds worldwide reach this grade, which makes it fairly understandable why they carry a premium.

5.1 Super Ideal (Hearts & Arrows)

Although it is not an industry standard and not a sixth grade, the ‘Super Ideal’ cut deserves a mention. It describes stones cut to a tighter tolerance than the top grade requires, with an even hearts and arrows pattern under a viewer.

Retailers give these lines their own names. Blue Nile calls its line Astor by Blue Nile, and James Allen used to label its version True Hearts before the brand moved into Blue Nile.

Is the premium worth paying? We’ve written the honest answer in our Astor vs Ideal cut comparison, and the short version is that the extra is a craftsmanship purchase, not a rescue from a dull stone.

Good vs Very Good Cut Diamonds: What’s the Difference?

Very Good returns clearly more light than Good. A Good cut is usually shaped to save weight from the rough, so the crown or pavilion angles sit outside the sweet spot and part of the light leaks away. Very Good stays near ideal proportions and loses very little. Side by side, Good looks sleepy.

The price gap is smaller than most buyers expect. For 1 carat, H color, VS2 clarity rounds, the ranges we recorded were $3000 to $3700 for Good and $3500 to $4700 for Very Good.

So you are paying a few hundred dollars, at the bottom of both ranges, for a jump in light return that anyone can see without a loupe.

In twelve years of inspecting stones for readers, we’ve found the gap is harder to catch under half a carat and impossible to miss from 1 carat upward, where the table is wide enough to show every leak.

Two rounds we found on Blue Nile made the point neatly: same color, same clarity, same weight, and the only difference on paper was the cut grade, yet the Very Good stone held its flashes while the Good one went flat as the video rotated.

Feel free to run the same test on the certified round diamond search, filtering one grade at a time and comparing the table and depth percentages listed on each report.

Our verdict: skip Good. Treat Very Good as your floor and Excellent as your target.

Excellent vs Ideal Cut: Which One Is Better?

They are the same tier in almost every listing you will read. Ideal is the retail word for the top of the scale, Excellent is GIA’s word for it. The one real distinction is AGS, which grades 0 to 10 and calls its top result Ideal (AGS 0), applying slightly tighter tolerances than GIA Excellent. Neither beats the other visibly.

Where it gets confusing is that a few retailers stack their own terms on top: Ideal, then Super Ideal, then a branded line. Those are marketing tiers, and the certificate underneath still says Excellent.

So what actually matters? The report. A GIA Excellent round with strong polish and symmetry is the safe buy, whatever the product page calls it.

And here is the part nobody sells you: shaving your table percentage a point or two closer to the textbook figure changes nothing your eye can catch. Get the grade right, then stop measuring.

Two of the finish grades feeding into that verdict are worth a read on their own: how diamond symmetry grades affect brilliance and what diamond polish is and how it moves the price.

Brilliant Cut vs Excellent Cut: Not the Same Thing

A brilliant cut is a faceting style, most famously the round brilliant with its 58 facets, arranged to maximise light return. Excellent is a grade describing how well that style was executed on a given stone.

So yes, you can have a round brilliant with a Good cut grade. The style promises the potential; the grade tells you whether the cutter delivered it.

What Factors Make a Diamond Cut Grade?

Five things decide the grade: proportions (table, depth, crown, pavilion, girdle), the symmetry and placement of the facets, the polish on each surface, and the three light effects those produce, brilliance, fire and scintillation. A lab measures the first three and grades the stone on how well they combine to return light.

Let’s break it down for you, factor by factor.

1. Diamond Proportions

The proportions of a diamond, particularly its table, depth and width, carry most of the cut grade. Ideal proportions capture light and send it back out of the top, instead of letting it drain through the sides.

Table

The table is the flat top surface, and its size relative to the diamond’s diameter is one of the most reported numbers on any listing. A well-proportioned table lets light disperse properly instead of washing out the pattern.

Depth

Depth is the height from the table down to the culet, expressed as a percentage of width. Too deep or too shallow, and light leaks instead of reflecting.

Crown

The crown is the upper section, stretching from the girdle to the table. It refracts entering light and does much of the work behind a stone’s dispersion.

Girdle

The girdle is the widest part of the stone and the boundary between crown and pavilion. It gives the setting something to grip, and an extremely thin girdle raises a chipping risk.

Pavilion

The pavilion runs from the girdle down to the culet. Its angles are the single most sensitive measurement in the whole stone, because they decide whether light bounces back up or exits the bottom.

Culet

The culet is the tiny facet at the very bottom. Ideally it should be none or very small; a large culet shows through the table as a grey dot.

2. Symmetrical Diamond Facets

Facets are the mirrors and windows that surround the table, above and below the girdle, ending at the pavilion. A round brilliant carries 58 of them.

The magic sits in their precise symmetry, size and placement. Misaligned or unevenly sized facets scatter light instead of directing it, and the stone loses contrast.

3. Brilliance

Brilliance is the white light you see coming back out of a diamond. Light enters, strikes the facets, bounces between those mirrors and returns to your eye.

A well-cut stone shows high brilliance and reads bright even in poor lighting, which is where most people actually wear their rings.

4. Fire

Fire, or dispersion, is the rainbow. White light entering the crown splits into spectral colors inside the stone, then flashes back out as independent beams of red, blue and orange.

Do you see those colored sparks when a ring passes under a spotlight? That is fire, and a shallow stone gives you very little of it.

5. Scintillation

Scintillation is what happens when the diamond moves. It is the pattern of light and dark flashes across the surface as the hand turns, and it is the effect people notice from across a table.

Brilliance and fire can be judged in a still photo. Scintillation cannot, which is exactly why a 360-degree video is worth more than any product shot.

What Is the 60/60 Diamond Cut Rule, and Does It Work?

The 60/60 rule says to buy a round diamond with a 60% table and a 60% depth. It is a rough shortcut, not a standard: plenty of 60/60 stones are gorgeous, and plenty leak light because the crown and pavilion angles behind those two numbers were wrong.

Depth percentage is the stone’s height divided by its width, and table percentage is the table’s width divided by the stone’s width. Neither figure says anything about the angles that actually steer the light.

GIA and AGS both grade on the full set of proportions and on measured light return, which is why a stone outside 60/60 can still earn Excellent.

Use it as a starting filter, then check the report. The full ranges per shape are in our guide to the ideal proportions for table and depth.

Why Don’t Fancy Shapes Get a Cut Grade?

GIA issues a cut grade for round brilliants only. For ovals, pears, cushions, emeralds and the rest, the report shows polish and symmetry but no cut grade, because there is no single agreed ideal set of proportions for those outlines. You judge them by measurements, by video, and by your own eyes.

That puts more weight on you, not less. On an oval, for instance, the thing to hunt for is the dark band across the middle, and our guide to the bow tie effect in oval diamonds shows how to spot one before you pay for it.

Rounds return the most light of any shape by a clear margin, which is part of why they carry a premium; the reasons are set out in why round diamonds sparkle more.

1 Carat Round Diamond Prices by Cut Grade

Holding everything else steady at H color, VS2 clarity, 1 carat and a round shape, the ranges we recorded were $3000 to $3700 for Good, $3500 to $4700 for Very Good, and $4200 to $5500 for Excellent. So the whole span from the grade you should avoid to the grade you should buy is roughly the cost of the setting.

Those figures move with the market, with lab certification, and with fluorescence, so treat them as the shape of the curve rather than today’s till receipt.

To check where the numbers sit right now, feel free to open the 1 carat round diamond search and sort by price with the cut filter set one grade at a time.

Notice what the curve says. Dropping a cut grade saves you a few hundred dollars on a 1 carat stone, while dropping a color grade or a clarity grade usually saves you more and costs you less in appearance.

How Should You Choose the Right Cut Grade?

Set the cut grade first, then spend whatever is left on carat, color and clarity. Buy Excellent or Ideal on a round if you can reach it, Very Good if you cannot, and nothing below. Then take your savings out of clarity and color, where the eye forgives far more than most buyers believe.

We usually recommend the lowest eye-clean clarity you can find, often an SI1 grade, and we rarely see a reason to pay above G or H color in a white metal setting. On cut, we go the other way and tell you to spend.

Read the report, not the product name. “Ideal”, “premium” and “signature” are retailer words; Excellent, Very Good and AGS 0 are lab words.

Watch the video before the specs. A 360-degree rotation shows leakage and dead zones that a table percentage never will.

Check polish and symmetry. Very Good or better on both keeps the top grade honest, and a Fair symmetry on an Excellent cut is a warning sign.

Compare like with like. Lock three of the 4Cs, change only the cut, and let your eyes decide the rest.

Remember, each diamond is unique, and its cut plays a pivotal role in showcasing its individuality and brilliance.

Summary: Final Words on Diamond Cut

Cut is the grade that decides whether your diamond looks alive. Clarity and color arguments are settled with a loupe; cut is settled from across the room.

GIA’s scale runs Poor, Fair, Good, Very Good, Excellent. Buy the top of it, accept Very Good if the budget says so, and walk past Good however friendly the name sounds.

Excellent and Ideal are the same tier under two labels, Super Ideal is a house tier that GIA never certifies, and a brilliant cut is a faceting style rather than a grade.

Get the cut right and a smaller stone will outshine a bigger one every single time.

Frequently Asked Questions on Diamond Cut

What is the difference between an Excellent cut and an Ideal cut?

In practice, nothing. Ideal is the retail term for the top cut tier, Excellent is GIA’s term for it, and most listings use them interchangeably. The only technical difference is AGS, which grades 0 to 10 and labels its top result Ideal (AGS 0) with marginally tighter tolerances than GIA Excellent.

Is a Very Good cut diamond good enough?

Yes, Very Good is a legitimate buy. These stones return nearly all the light entering them, and they cost less than Excellent for a difference most people need a side-by-side comparison to catch. We still push for Excellent when the budget allows, even at a slightly lower carat weight.

Is a Good cut diamond worth buying?

We wouldn’t buy one. Good cut is really bad in light-return terms: the angles sit outside the sweet spot to save weight from the rough, so the stone looks flat next to a Very Good. On a 1 carat round the price gap between the two grades is a few hundred dollars.

Can you see the difference between Good and Very Good with the naked eye?

At 1 carat and up, yes, easily, especially when the stone moves. Under half a carat the gap narrows because the table is small and the eye has less to read. Watch the 360-degree videos of both grades rotating before you decide.

Is a brilliant cut the same as an excellent cut?

No. Brilliant cut is a faceting style, most commonly the 58-facet round brilliant. Excellent is a grade describing how well the cutter executed the proportions, symmetry and polish. A round brilliant can carry any grade from Poor to Excellent.

Does cut affect a diamond’s price?

It does. For 1 carat, H color, VS2 clarity rounds, we recorded roughly $3000 to $3700 for Good, $3500 to $4700 for Very Good, and $4200 to $5500 for Excellent. Only 3-5% of diamonds worldwide reach the Excellent grade, which explains the premium.

Which cut grade should you buy on a tight budget?

Very Good cut, then save elsewhere: drop to an eye-clean SI1 clarity and an H color before you ever drop the cut grade. If the budget is tighter still, a lab-grown stone at Excellent cut beats a natural stone at Good cut on looks, every time.

Still not sure where to buy your diamond?

Start with certified stones you can inspect on video before paying, and compare grade by grade rather than price by price. Feel free to browse the certified loose diamond inventory at Blue Nile, or look through the finished engagement ring settings if you already have your stone picked.

If you’d rather read our full verdict first, we’ve covered the store in our Blue Nile diamonds and jewelry review.