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Anatomy Of A Diamond: Everything You Need To Know

Anatomy Of A Diamond: Everything You Need To Know

When shopping for a diamond, its sparkle and brightness are undeniably going to draw you to the jewelry counter and keep you captivated for a long time. But this stunning look wouldn’t be possible without making sure that every section of the diamond is professionally cut, though.

Now, while searching for a diamond, you’ve probably heard the term anatomy of a diamond. So, the question is, would you know in what sections the diamond is divided?

Apart from the main structural elements of a diamond, there are some other things you need to be aware of that are included in the diamond’s anatomy. 

Don’t worry, though. We covered every part of the diamond in this article. 

So, without further ado, let’s find out more about the anatomy of a diamond!

Diamond Structure

While diamonds come in many sizes and shapes, there are five structural components that all diamonds share. The angles that these five components create dictate how much light the stone can reflect and, in turn, how brilliant it is.

Table 

The table is the flat, topmost surface area of a diamond. It’s the most significant facet, no matter the diamond’s shape.

A diamond’s table refracts light downwards as it enters the gem. In turn, the light’s reflected from the pavilion and through the table. Therefore, most of the diamond’s light reaches the observer’s eye through its table.

The amount of light that’ll enter the stone is determined by the size of its table. Thus, it’s an essential factor gemologists use when they assign a diamond cut grade.

Crown 

A diamond’s crown surrounds everything that is above the diamond’s girdle.

Similar to the table, refracted light passes through the crown, reflecting back from the pavilion into the observer’s eyes. The various facets of the diamond’s crown disperse light in different directions making a colorful and stunning fire.

Girdle 

That’s the widest part of the diamond and the outermost edge where the diamond’s crown and pavilion connect. 

When placed in a bezel or halo ring setting, the gem’s girdle is usually hidden and level with the precious metal as it meets the stone. In a channel or prong ring setting, the girdle can be seen where no metal touches the gem.

Diamond experts consider a diamond’s girdle width when determining a diamond’s cut grade. If the girdle is too thick or thin, they will assign a Very Good or Good cut quality even if the gems offer a lot of sparkle and structural stability.

Pavilion 

The pavilion is the area that starts at the girdle and ends at the culet.

The bulk of a stone’s weight is usually held in a pavilion. That means it’s generally considered the most valuable portion of a diamond, yet its angles are much more important than its physical size.

It’s crucial for a pavilion not to be too shallow or too deep. 

When viewed from the table, a shallow pavilion creates a “fish-eye” effect, caused by the gem’s girdle reflecting in the middle of the table, looking dull and lacking sparkle.

A too deep pavilion brings a darkened effect to the stone since it doesn’t reflect as much light to the observer’s eyes through the diamond’s crown.

The optimal pavilion percentage falls between 42.5% and 43.5%.

Culet 

That’s the very bottom of the stone’s pavilion. It’s either a point or a tiny facet that lies parallel with the diamond’s table. If the culet is a facet, it can be either polished or unpolished.

If a culet is more prominent than average, it could impact the overall appearance of a diamond. 

When observing through the diamond’s table, a large culet may be visible when set in a ring. A larger culet allows more light to escape through the bottom of the stone – rather than reflecting it to the observer’s eyes, causing a noticeable dark circle.

Diamonds with small culet, on the other hand, are likely to exhibit the most brilliance.

Diamond Proportions

When diamond experts grade diamonds, they measure the proportions and calculator five ratios which are pavilion angle, crown angle, table percentage, and depth percentage.

These ratios help evaluate the diamond’s cut grade and are contained in the grading report.

Depth Percentage

The depth percentage is one of the critical characteristics in evaluating a diamond’s cut grade. 

The depth percentage refers to the ratio of the distance between the culet to the table and the stone’s diameter measured across the girdle.

Depth should measure from 54% to 66% of the gemstone’s diameter to optimize its sparkle. On that note, diamonds with Very Good and Ideal cut grades have a depth percentage within this range.

Table Percentage

The table percentage is all about balancing the diameter of the gem and the width of the table to create optimal sparkle.

If the table’s width is too small or too big compared to the stone’s diameter, the top of it will look rounded or flat. And either way, the sparkle will be compromised.

The perfect table percentage is between 53% and 70%.

Crown Angle

If the crown angle is too big, the sparkle will be compromised when viewed from above. On the flip side, if the crown angle is too small, the diamond’s top area could appear glassy and clear.

Diamonds cut with an optimal crown angle will yield more sparkle and fire. Most round brilliant diamonds are cut to have a crown angle between 32 and 36 degrees. 

Related Read: Fire In A Diamond? What is Diamond Fire?

Pavilion Angle

As with the crown angle, if the angle of the pavilion is too large, it won’t emit much sparkle. And if it’s too small, the diamond could appear glassy. 

When cut for optimal brilliance, the pavilion should reflect the most sparkle through the top of the stone to your eyes.

The optimal angle of the pavilion is within the range of 42 to 43 degrees.

Diamond Symmetry

When grading a gem, a diamond expert assesses the symmetry of the stone’s facets. Symmetry is a crucial element in a diamond’s cut grade, reflected in the pricing of a precious stone.

A diamond with excellent symmetry may cost up to 10% to 15% more than a stone with a Good symmetry grade.

Why is symmetry important? 

When the diamond’s facets are perfectly aligned, the light that enters the gemstone is reflected back, producing brilliance. However, when the facets don’t align well, less of the light that enters the diamond gets reflected, thus creating dark spots.

Diamond symmetry is rated from Excellent to Poor. Excellent symmetry indicates that all facets are perfectly aligned. 

A diamond’s symmetry can be affected if the table and the culet are off-center, if the girdle isn’t straight, or if the facets are misshapen. A misalignment of the girdle and the crown are deemed symmetry flaws, too.

The symmetry grade of a diamond that’s certified is shown on its grading report. 

Diamond Inclusions And Blemishes

A diamond’s clarity grade depends on how prominent and how noticeable its inclusions and blemishes are. On that note: 

Cavity

A cavity is essentially a hole in the surface of the diamond – and can be found in different sizes and locations across the stone. Based on its location, a cavity could impact the overall durability of the diamond. 

Cavities located on the diamond’s table are likely to be most noticeable when set in jewelry, thus compromising the stone’s quality and value.

Chip

Sometimes created during the cutting process, chips are shallow indentations found at the diamond’s surface.

Clarity plot reports will specify where chips are located. If the chip is near the stone’s edge, you may set it in a way that hides it or makes it less visible. 

Clouds

Clouds refer to groupings of unique slight inclusions that can’t be distinguished from each other – even under magnification.

They appear as a translucent cloud within a diamond and can’t be seen without magnification. Because of this, clouds generally don’t impact the clarity grade.

Related Read: Why Do Diamonds Get Cloudy?

Crystals

You can also find crystals of other minerals included within the bigger structure of the diamond. 

While often a crystal will be a smaller diamond within the bigger one, they can also be garnets, emeralds, rubies, etc. Dark crystals of carbon are also common.

Crystals can be found in a variety of colors, sizes, and locations. If they’re colorful and easy to notice, they may impact the clarity and value of the diamond.

Related Read: Diamonds Vs. Crystals: What Is The Difference?

Feathering

Feathering is a fissure inside a diamond created millions of years ago – during the formation process of the diamond. The size and location of a feather can impact the clarity grade of the diamond. But if it’s located near the edges, prongs can hide a feather. 

So, feathers are only considered a durability issue if located near the diamond’s girdle or as an opening on the diamond’s surface.

Knot

A knot refers to a diamond crystal inclusion that breaks the surface of the finished gem. Under intense magnification, the difference between such inclusions and the bigger stone should be clear.

Depending on the size of the knot within a diamond, you might even be able to feel it if you run your finger over the stone.

Indented Natural

Technically a blemish, a “natural” is an unpolished section of the diamond. Originally part of the rough diamond’s outer layer, these are often found on – or around – the diamond’s girdle.

If naturals travel to the diamond’s crown or pavilion, they’ll be considered indented naturals. But while indented naturals are included in a clarity plot, they don’t impact the durability and overall quality of the diamond.

Unlike other inclusions or blemishes, naturals have always been present – and have generally been appreciated as a reminder of the stone’s organic history.

Needle

A needle looks similar to a feather inclusion but with just one long, narrow line. Often, they don’t impact the light return from the stone and can be either transparent or white.

Some needles can be pretty long, though, making them more noticeable than others.

Pinpoint Inclusion

Usually, a pinpoint inclusion is what separates a VVS1 from an IF clarity grade. Given that they appear as a mere speck inside a diamond, they’re often detectable under high magnification.

Pinpoint inclusions don’t impact the overall durability of the diamond.

Twinning Wisp

A twinning wisp is the result of growth defects within the crystal structure of a diamond. These inclusions that have twisted together are most commonly found in fancy-shaped diamonds. 

With a white striped appearance, a twinning wisp is generally more visible than other inclusions. 

Diamond Polish

Once a diamond’s been cut, it’s then polished to reveal a smooth finish. Every facet is polished on a wheel – as a result, the diamond’s sparkle is improved.

During the polishing process, the wheel can make subtle scratches on the surface of the stone. And yes, almost all diamonds have remnants of these polishing marks on their surface.

If the scratches are large enough, they could misdirect light that enters the stone, thus decreasing its brilliance.

Once the process is complete, a diamond expert will evaluate these defects, after which they’ll assign a polish grade. You can find that grade on the grading report.

Diamonds with no noticeable polish defects are assigned with a grade of Excellent. Very Good and Good polish grades indicate that the defects are difficult to see, even under magnification. 

See Also: Is IGI As Good As GIA?

Final Word

To understand what makes diamonds as beautiful as they are, you first need to understand the anatomy of a diamond. 

A diamond’s structure consists of several key components: table, crown, girdle, pavilion, and culet. Each of these requires specific positioning and size in order to make the diamond look beautiful and provide the perfect amount of sparkle.

However, almost all gems have naturally occurring flaws within them called inclusions. There’s nothing inherently wrong with diamond having an inclusion, but some types of these inclusions can affect the stone’s overall beauty or durability.