How Do Cavity Inclusions Impact Diamonds? (+Buying Advice)

Diamond cavities: Do they make or break diamond clarity?

Some diamond inclusions are more apparent than others. Diamond cavities are no exception, and they can be an eyesore as well as a danger to a stone’s durability. Like other inclusions, cavities can define a diamond’s clarity grade, and it’s important to know when a particular cavity is just a minor imperfection or a grade-setting characteristic.⚖️

But what exactly are cavities? We’ll break down all you need to know about diamond cavities below, including:

• Diamond cavity basics
• Ways cavities form in diamonds
• A cavity’s potential impact on a diamond
• How diamond cavities relate to clarity
• Cavities vs. similar inclusions
• Treating diamond cavities

Basics: What is a cavity in a diamond?

A diamond cavity is much like a cavity in your tooth: it’s a hole in the basic structure of the diamond. However, unlike the decay that causes dental cavities, a cavity in a diamond is the result of a feather inclusion breaking away or a surface crystal falling out of the stone either naturally or via the crafting process.

Diamond cavities form crevasses in the surface of the gem, but how impactful they are to the stone’s overall beauty depends on their size. Cavities can be microscopic or large enough to see with the naked eye, and they can be found anywhere on a diamond’s surface.🔍

Furthermore, how impactful a cavity is to a diamond’s durability depends on its location, size, and position relative to the rest of the stone. We’ll discuss the durability risks posed by cavities later.

Two common ways diamond cavities form

Diamond cavities can occur naturally during the diamond formation process, but they often appear as craftsmen cut, brute, and polish the stone. During the latter process, apart from forming accidentally, sometimes diamond cutters decide whether to leave or remove the cavity based on whether the removal would cause a severe weight loss for the overall gem. In either case, here are the two major ways diamond cavities form:📋

• First, a feather inclusion can breach the surface of a diamond and dislodge, forming a cavity within the stone. This can happen during the polishing process, where heavy machinery and intense pressure can impact the feather and result in a hole.
• Second, a crystal inclusion (known as knot) can dislodge from a diamond and leave behind a void. Crystals being pushed out of diamonds can happen naturally during the intense diamond formation process, but it can also occur when diamond cutters remove large, dark inclusions from gems for the sake of overall clarity.

In either case, diamond cavities can cause little to no threat to a diamond’s wellbeing in some instances. However, there are situations where a cavity can pose a major threat, and we’ll discuss the impacts a cavity may have on a diamond’s appearance and structure below.

How do diamond cavities impact a diamond’s beauty, durability, and value?

So how exactly do cavities affect diamonds? Let’s take a look at a few factors regarding the impact of cavities and the factors that lead to deeper issues:

Appearance

Cavities can affect a diamond’s light performance, hindering its trademark sparkle.✨ Depending on size and location, a cavity can change how light enters and exits from a diamond, therefore directly affecting brilliance.

Location is key here, as cavities found under the diamond’s table or near the pavilion pose a greater risk to light performance. In contrast, cavities near the girdle or crown can still affect light play but to a lesser degree.

Additionally, cavities can cause dirt, grime, and excess oils from your skin to collect within their crevasses. The resulting debris is difficult to clean out, meaning your diamond could end up with a dark spot where the cavity is.

The best way to discern whether a cavity may pose a problem to a diamond’s light performance and appearance is to study the diamond plot provided in the stone’s grading report and inspect it yourself. The grading report can help you locate all cavities within the diamond and determine their location, while inspecting the diamond can give you an idea of whether the cavity is noticeable with the naked eye or if the diamond passes as eye-clean.📝

Durability

Diamonds are tough, but cavities can increase the chances of chipping around the edges of your stone if they’re near the edge. What’s more, a diamond’s shape can impact how much a certain cavity will affect it.

Cavities near the center or bottom of a stone pose less risk, but those near corners and edges are more of a threat. For instance, a princess-cut diamond could have cavities near any of its four corners or edges and be in danger of chipping. The same can be said for any shape with points—marquise, radiant, Asscher, etc.—as well as any shape with edges…so all of them!

One way to combat a cavity in a bad location is by selecting a protective setting for your diamond. Because more chipping will occur when the diamond impacts a hard surface, choosing a stronger, more comprehensive setting, such as a bezel setting, can protect the edges of your diamond from further harm. Prong settings are also great for covering any cavities on the corner of your diamond, and you can even opt for a double prong setting for further coverage.

Value

The larger the cavity, the more likely that it will impact the diamond’s price. However, this is true for most imperfections, as larger or more noticeable inclusions and blemishes lead to lower clarity grades. This is especially true if the inclusion impacts the stone’s durability.

Prices for diamonds decrease as clarity grades decrease, and cavities can be found in diamonds with grades lower than IF. So, while the cavity may or may not be solely responsible for a lower price, the presence of visible cavities and inclusions will determine the stone’s value. In fact, prices typically fluctuate by 8-20% as clarity grades decrease.

Cavity inclusions and diamond clarity grade (Plus advice)

So how do diamond cavities play into diamond clarity, and how can you avoid buying a stone with less than desirable inclusions? We’ve gathered some advice below to aid you on your shopping journey:😚

Clarity grades where you’ll find cavities

As we mentioned above, the clarity grades containing cavities are VVS to I; but you would find them mostly in the SI-I range. How visible these cavities are—if there are any at all—depends on the five clarity factors (size, nature, location, number, and relief) as well as the diamond’s cut and color quality.✅

When cut, color and carat characteristics are equal, how visible a cavity is can determine what type of clarity grade the overall diamond will receive. As such, it’s important to take a holistic approach to examine a diamond and how its different quality grades interact.

Avoid large cavities

If you can, try to avoid diamonds with large, deep cavities during your search. Larger cavities attract dirt and grime, and even the oils from your skin can build up in these fractures and cause your diamond to appear darker. This is even more important if the large cavity is on the pavilion of the stone, as it’s harder to reach once the diamond is set and can leave dark spots under your ring that a jeweler can’t easily clean.

Location, location, location

As we mentioned before, a cavity’s location is crucial. Cavities near the pavilion or table pose the greatest risk to the stone’s appearance, whereas those near the girdle or crown are more forgiving.

Cavities in step-cut diamonds can be tricky as well, as the mirrorlike glow of these cuts can actually make inclusions more noticeable. This is especially true when dirt or oils build up in these areas.

Diamond cavities vs. Other related inclusions

There are many different inclusions you may come across as you read a diamond’s grading report. Here are a few common inclusions and how they compare to diamond cavities:

Cavities vs. Feathers

A feather is a small fracture or crack in a diamond, and it can be internal or external. These breaks often look like feathers, as the tiny fissures spreading from the main crack give it a feathery appearance.

Unlike cavities, feathers can be white or dark colors, and they can be found inside diamonds rather than just on their surface. However, much like cavities, feathers can be microscopic or large enough to view with the naked eye. They can also cause durability issues depending on where they are located on or within the diamond.

Cavities vs. Knots

If you notice a knot on your diamond grading report, this is a small crystal that breaks through to the surface of your diamond. Knots appear during the finishing and polishing process, and they can be white or transparent.

While cavities look more like chunks of stone have been removed from your diamond, knots sometimes look like raised areas on the surface of your gemstone. Consequently, if the crystal was dislodged in any way, the resulting hole would be a cavity, so these two inclusions are connected!🔗

Cavities vs. Indented naturals

Indented naturals are portions of rough diamond left untouched during the polishing process. These unpolished sections dip below the stone’s polished surface, almost like a small, unfinished hole in the diamond.

It can be difficult to distinguish between these two inclusions! Cavities and indented naturals can look similar, but indented naturals are usually found on a diamond’s girdle. In contrast, cavities can be found on pretty much any surface of a diamond. Indented naturals are not also the result of a removed crystal or feather, but rather just an unpolished surface that was left alone by the diamond cutter.

Cavities vs. Chips

Small, shallow openings on a diamond’s surface, chips are typically caused by damage to the stone. Wear and tear over time or accidental rough contact can cause chips to form if you’re not careful, and they’re found near the culet, girdle edge, and facet junctions.

Chips and cavities can both be man-made, but cavities are the only inclusion of these two that can actually form naturally. These two inclusions also form in similar areas, although cavities can be found anywhere on a diamond’s surface. A chip can even occur AFTER you purchase your diamond, because not taking care of your ring or hitting your diamond on a hard surface at just the right angle can cause chipping.

Can diamond cavities be treated? Two methods explained

So can cavities be treated? For the most part! There are two ways experts treat cavities to decrease their severity or fill them altogether. Here are the two most common ways diamond cavities are treated:

Fracture Filling

Similar to feathers and other small inclusions, cavities can be filled with a glass-like resin to diminish their effects. The resin fills the small cracks around the cavity as well to produce a more consistent appearance. However, once a cavity is filled, the diamond can no longer be considered “natural” as it has undergone impermanent enhancement, which lowers its value relative to untouched natural stones.

Deep Boiling

The only process recognized and authorized by the GIA, deep boiling involves submerging a diamond with cavities in an acidic solution and subjecting the stone to intense pressure. During this process, any grime accumulated within the cavities will dissipate, making the cavities less noticeable. However, it should be noted that this process does not remove the presence of cavities.

Diamond cavities are a personal choice

While not all diamond lovers may be comfortable with even the smallest cavity out of fear of the inclusion causing issues, many shoppers are less intimidated. To some, as long as the cavity isn’t massive or doesn’t cause any structural issues, it’s really not a thing of concern. Like all other inclusions, diamond cavities are a matter of personal taste, and being willing to accept some cavities may be able to save you money as you shop for a diamond.

As we mentioned above, one of the causes of diamond cavities is the removal or chipping away of feathers, another common inclusion. Learn more about diamond feathers here to educate yourself further on diamond inclusions, how they form, and how to spot them.