Blog Banner
Twitter koamaruFacebook koamaru


Everything you Know About Diamond Cut Grades is Wrong (the Fancy Shape Edition)

By Stephanie Dore

Confused about diamond cut grade? Everything you need to know to shop fancy shaped diamonds and a free try-at-home kit to make engagement ring shopping easy!

Ahh, cut grade. The most important—and most confusing—of the 4 Cs. Color, clarity, carat weight, those all make, well, common sense. But cut grade? Cut grade is confusing. I mean, is it about the shape of the diamond? The proportions? The sparkle? All of the above? Exactly. Cut grade takes into account all the itty bitty factors that make your diamond truly brilliant, or unfortunately not. A low cut grade can mean a dull diamond, and no one wants that. But what happens when cut grades are only assigned to round diamonds—and you want an oval? Or an Asscher? Or a cushion? Oh my. Welcome to the fancy shaped diamond dilemma. To help you out, we’re breaking down the need-to-knows of diamond cut grade, and why you should throw it all out the window. Kind of.

The Shape Shift

So, here’s the story. Back in the day, the GIA referred to a diamond’s cut only as “made well” or “made poorly”. And gosh darn it, that just didn’t cut it. So some super rad gem geeks spent years, decades, mulling over the scientific processes necessary to identify exactly how a diamond’s cut—it’s appearance, proportions, and symmetry—affected it’s brilliance. And in 2006, they landed on it! 

Granted, it took loads of extensive research…and they only created a grading scale for round diamonds. What?!?! Yep. See, about 70% of diamonds on the market are round brilliant cuts. They’re the most perfected, standardized, studied shape of diamond out there. Thus, much easier to compare and therefore land on a scale of poor to excellent that we still use today.

But We Fancy Now

I know, I know, it’s a real bummer. But fancy shaped diamonds are just that—fancy. And each one is so unique that no one has ever really figured out a consistent way to compare them that offers any kind of guarantee of whether a diamond will sparkle or not. There are just far too many miniscule variables to measure.

In fact, GIA’s site says this: “An internationally accepted system for visually evaluating the appearance of fancy-cut diamonds does not exist at this time. At GIA, research is underway to develop the basic concepts for designing and implementing such a system.” But let’s not hold our breath.

A 2.5 carat Asscher diamond
set in Mason No. 5
3 carat round brilliant
set in Harper No. 1 Two Tone

The Nitty Gritty

For your basic understanding, GIA’s round diamond cut grading scale is made up of seven components. Brightness (the light reflected out of a diamond), fire (the rainbow flashes), and scintillation (the pattern of sparkle when a diamond is moved) are all appearance-based, while weight ratio, durability, polish, and symmetry are related to a diamond’s design and craftsmanship.

Still With Me?

The first thing to know about fancy shaped diamonds is the two different faceting styles you’ll most often see. First, you have brilliant cut facets, which—like the round diamond—are facets that radiate outwards from a center point like rays of the sun. Then you have step cut facets—like the emerald or Asscher—which are elongated, rectangular facets that give you that “hall of mirrors” effect. Then there are the mixed cuts. Which might be any combination of these, or additional faceting patterns. See. Messy.

Take Extra Measures

Many fancy shaped diamonds can appear larger than rounds of a similar carat weight, so if you’re looking for something that saves you some money but sparkles large, they can be a great option. Just make sure to check out their measurements, including length to width ratio (this will tell you how elongated or squatty the overall shape is), depth percentage and table percentage (which will help you understand a diamond’s light return), and the girdle and culet sizes.

Wait, what?

Ok, so the girdle is the outer rim of your diamond, where the top (crown) and bottom (pavilion) meet. It’s quite thin, thus making it an area of caution, however it does have actual thickness to it, and will be measured anywhere from very thin to extremely thick, in comparison to the diamond’s overall depth. You don’t want it too thin (hello, chips) or too thick (hidden carat weight that you’re dumping dollars into).

And the culet is the name of the facet at the very bottom middle of your diamond, where all the facets come together. Again, a delicate spot (that will be protected in settings) that can be a drain on your diamond’s visual. Most round diamonds will be listed as “none”, but fancy shapes change it up a lot more, from very small to very large. Older, vintage diamonds are more likely to have larger culets, but this can also create a large dark spot in the center of your diamond, so make sure to take a look if you see a larger culet listed on your certificate.

Sidney No. 1 pave frank darling round diamond engagement ring set with a 3 carat round diamond cut
The girdle of the diamond is
the line where the top meets the bottom.
Shown here in Sidney No. 1 Pavé.
An oval diamond with a larger
bow tie and dark tips

Suited Up

Ah…the bow tie. It sounds like a good thing, but it really isn’t. Unfortunately, it’s a fact of life in many fancy shapes. It’s a bow-tie shaped dark area in the center of many elongated brilliant cuts like ovals, marquises, and pears. And while they all have it, a well cut diamond will minimize its appearance.

See the Light

These days, you can find reports like the ASET, or Angular Spectrum Evaluation Tool, which is a device developed to assess a diamond’s interaction with light. It creates a colorful reading of the light return of fancy shaped diamonds—also super helpful when evaluating bow ties! It’s not a be-all-end-all answer to brilliance but it can be a helping hand for sure.

An ASET of a 5.5
carat Asscher diamond

Putting Your Money Where Your Heart Is

Ultimately, if you’re feeling fancy, then you should go for it. Not only can it save you significant cash, but it can give you a totally unique look from all the other engagement rings out there. Just get eyes on it before you buy—whether that’s with photos, video, or in-person viewing—to make sure it’s got that good good sparkle. You can start with our diamond search where you can view 360-degree images of more than 10,000 diamonds.

Need a Little Help From Your Friends?

That’s what we’re here for! We offer a free, try-on service that provides a great way to see how different shapes will look on your hand, without ever leaving home. And we love hunting down the perfect diamond for your dream ring. Email us with what you’re looking for at We’ll curate a list of 5-7 exclusive stones that are just right for you.

Your cart is currently empty

View your wishlist or view all rings.