The Most Important of the ‘4Cs’: Diamond Cut

If you’ve done any research into buying a diamond, you’ve probably heard of the 4Cs: color, clarity, cut, and carat weight. While each factor defines a diamond’s overall appearance, most jewelers would agree that not all ‘Cs’ are created equal. There’s one element that arguably impacts diamonds’ beauty most: cut.

A diamond’s cut is what makes it sparkle. It’s the factor that fuels its fire. Cut is more than just the shape of a diamond – it’s its proportions and finish, the precise way its facets are fashioned, and what governs its interaction with light. A great cut can make a less-than-pristine diamond dazzle; a poor cut can dull the brilliance of a D, Flawless beauty.

So aside from that undeniable sparkle (or lack thereof), how can you really tell a good cut from the bad?

Let’s start with the most popular and traditional of shapes and cutting styles, the round brilliant.

What Makes a Round Brilliant Diamond Shine

The standard round brilliant-cut diamond has 57 facets (or 58, depending if it has a culet). Its facets are like tiny mirrors that reflect light from inside the gem to your eyes. If just one of those facets isn’t aligned correctly, or is improperly polished, the diamond’s cut grade will be affected.

In the technical assessment of diamond cut, seven main components are considered:

• Brightness: the light reflected from a diamond

• Fire: the dispersion of white light into a rainbow of spectral colors

• Scintillation: the pattern of light and dark areas, or the flashes of light seen when a diamond moves

• Length-to-Width Ratio: relation of the crown angle, average girdle diameter, table percentage, and pavilion angle measurements, among others

• Symmetry: how precise and balanced its proportions and facets are

• Polish: the condition of the facet surfaces (the absence of characteristics such as nicks, scratches, burn marks and polish lines)

• Durability: hardness, toughness, and stability (or how well it withstands heat, chemicals, and wear)

Fortunately, you don’t need to remember what each of these terms means – (but you’ll impress your jeweler if you do)! They’re just here to guide your understanding of cut quality, and all the elements that must come together for a diamond to have that “Wow” factor.

The Gemological Institute of America (GIA) spent over a decade researching the precise proportions and craftsmanship that yield the most attractive face-up appearance in diamonds. With this research – and thousands of observations by retailers, manufacturers, and the general public – GIA developed a universal diamond cut grading system, or a standard, objective way of assessing a round brilliant’s cut.

When you look at a diamond’s GIA Grading Report, you’ll see one of five diamond cut grades: Excellent, Very Good, Good, Fair, or Poor. The higher the grade, the brighter your diamond will sparkle.

Keep in mind that not all ‘Excellent’ or ‘Very Good’ cuts will appear the same, as within each category are natural variations in stones’ overall sparkle and appearance. That is why it’s key to view a stone in-person, and not just online. A trusted jeweler can help you spot the subtle differences.

Fancy-Shaped Diamond Cuts – What to Look for

Evaluating the cut of fancy-shaped diamonds (any shape other than round) is a bit more complex, as there is no standardized grading system. Still, there are certain proportions and characteristics that consistently produce maximum sparkle, and any trusted jeweler would be happy to help you identify them.

When it comes to emerald or Asscher cutting styles, clarity is king. This is due to the style of their faceting – the step cut. Unlike brilliant cuts, which have triangular and kite-shaped facets that can mask clarity characteristics, step cuts have long, narrow, four-sided facets arranged in parallel rows. Looking into a step-cut diamond is like looking into a mirror – if there’s anything in the stone, you’re going to see it – reflected multiple times!

Therefore, if you’ve got your eye on an emerald or Asscher cut diamond, aim for VS (Very Slightly Included) clarity or higher. Emerald and Asscher cuts also show their color more than rounds, so at Nuha we generally recommend I color or higher.

Oval and pear-shaped diamonds are a great alternative to traditional rounds – their brilliant cuts give them fire, and they tend to look larger than round brilliants of the same weight. Still, there are things you’ll want to examine to ensure your stone sparkles – like symmetry, length-to-width ratio, and shape appeal.

For example, shoulders – or the rounded ends of pear shapes and both ends of oval shapes – should be gently and evenly rounded, not square or distorted. While no diamond is perfectly symmetrical, balanced shoulders, culet placement, and facet alignment are key – if any of these are uneven, a diamond won’t sparkle as brightly.

In pears and ovals, and in other less common shapes like hearts and marquises, you’ll want to be aware of what jewelers call a bowtie. Severe bowties can occur when a stone is cut too shallow or deep, and appear as dark shadows extending from a stone’s center and running along its width. Most ovals, pears, marquises and hearts will have some degree of a bowtie, but those with the least noticeable effect are typically most desirable.

While these fancy shapes can yield larger-appearing diamonds, they also tend to retain diamonds’ color, so it’s advisable to move up on the color scale when possible.

Beauty is in the Eye of the Beholder

Remember: not all the elements that make one stone more attractive than the other are all listed on a GIA certificate. It’s always a good idea to view at least two to three stones in-person and side-by-side to see which shines brightest.

As jewelers, we can go on forever about what makes a diamond beautiful, but ultimately, that decision is up to you. Diamonds, especially fancy cuts, are a matter of personal taste. The info presented in this post isn’t meant to overwhelm you, but to give you the tools you need to make a purchase you feel good about.

At the end of the day, it’s really all about that one simple thing: sparkle!