What's the Crystal Inclusion? What're Its Impacts on a Diamond?

Diamonds are one type of crystal typically comprising 99.95% carbon. The orderly arranged and closely bonded carbon atoms enable diamonds to hit 10 on the Mohs scale.

Do you know there can be other crystals existing in such dead hard crystals/diamonds?🤔

These crystals do not link to the composition of diamonds and are treated as one type of inclusion that can decrease a diamond’s beauty and value. This article will walk you through crystal inclusions and give you helpful hints for your decision on buying these diamonds.

What are crystal inclusions in diamonds? How do they form?

Diamonds form under high-pressure, high-temperature environments causing them to have internal and external imperfections or growth characteristics.

Crystal inclusions are other minerals and crystals trapped inside the diamond during its billions of years of growing in the earth's mantle. These inclusions could be other diamonds, peridot and garnet crystals, or other unknown species forming into different shapes, colors, and textures. To date, researchers have been able to confirm and identify more than 24 types of crystal inclusions inside diamonds.📝

Crystals can appear transparent, white, gray, black, or tiny dots. They can be brightened or darkened as per different lighting conditions. Diamonds can contain many of these crystal inclusions in one stone, or just one crystal, depending on the formation. Crystals can appear as very, very obvious, or super tiny—this also determines the clarity grade.

How do crystal inclusions impact diamonds' beauty?

Crystals inside diamonds generally show up with a flat crystal plane and angular silhouette. Most crystals can only be seen under 10x magnification if they are small. Larger crystals may be seen with the naked eye if the diamond’s clarity falls into the SI category and below, resulting in a lower clarity grade and deemed lower quality with less value.

👉🏻Crystals that exist in a cluster especially located in the middle of the stone, can straightforwardly hurt the diamond's beauty and value. The diamond will showcase more and even distributed brilliance, fire and scintillation when without the interruptions of large crystals.

In some cases, some jewelers prize diamond crystals inside the diamond, making them center stage and amplifying their uniqueness. They appear as gorgeous mini diamonds forever trapped inside the main diamond. The diamond cutter artistically cuts around these crystals, incorporating them into the finished design.

Colored crystal inclusions growing inside the diamond, such as garnets, make them rare stones to find, intriguing and gorgeous. Depending on where the crystal is located, the diamond can be fashioned to reflect it in all facets, creating a mirror-like effect.

Crystals vs. Knots & Cavities

Diamonds contain a mesmerizing amount of internal characteristics, making them even more fascinating, with each a true treasure. Although diamonds contain both blemishes (exterior) and inclusions (interior), inclusions can break through the surface, causing durability problems for the stone.

What are some other inclusions besides crystals commonly found in diamonds? A cavity is an angular opening on the diamond. A cavity can occur for different reasons: when a part of a feather breaks away, when a surface-reaching crystal drops out of the stone, or is forced out during the polishing process. A cavity is different from a crystal because it is a negative area or hole.⚖️

Knots are a white or transparent diamond crystal that extends to the surface after cutting and polishing. Knots are usually very visible, appearing on the surface unlike a crystal inclusion, which remains inside the diamond. Both knots and cavities potentially make the diamond weaker and the clarity grade lower due to their nature. When diamonds are graded SI2 and below, the diamond’s integrity may be compromised because of the type of inclusions it contains.

Can crystal inclusions be removed? How?

Laser drilling can remove the visibility of a darker crystal. A man-made insertion creates a tiny tunnel in the diamond aiming at the inclusion. An acid is introduced under pressure, dissolving the inclusion by inserting it through the tunnel. This reduces color and size but does not alter the actual clarity grade.

Laser drilling a diamond creates a surface-reaching drilled hole. It can also expand a pre-existing feather around a dark inclusion, allowing it to reach the surface. The drilled hole or feather allows for bleaching, decreasing the visibility of the inclusion by reducing its color. Fracture filling is another way to further diminish the appearance of a crystal inclusion—like bleaching, injecting the diamond with a glass-like resin. This resin fills and seals negative space and tiny cracks, making inclusions significantly less noticeable. By laser drilling, bleaching, and fracture filling, crystals become less visible with color and size.

Fracture filling and using resins and other material is not permanent. This filling can change color or dissolve over time due to its unstable nature. Fracture filling makes the diamond ineligible for professional diamond grading because it is altered or “treated” BUT impermanent. These treatments also affect the diamond’s value.

Do lab-grown diamonds have crystal inclusions?

Lab-grown diamonds DO NOT have crystal inclusions because they are synthesized in a lab, not forming in the earth's mantle with other crystals. Lab-grown diamonds may contain inclusions that grow during the formation process resembling crystals that are metallic flux (HPHT lab-grown diamonds) and dark graphite or other mineral inclusions (CVD diamonds).

The types of inclusions in a lab-grown diamond vs. natural diamond help identify the origin of the diamond, making them all the more fascinating.

Buying diamonds with crystal inclusions

Buying diamonds with crystal inclusions is a common occurrence, as many diamonds do contain such growth characteristics. Crystal inclusions would become easier to spot when the diamond is graded at SI1 and below. (sometimes, you can even notice them with the naked eye when at VS2)

With the aid of a diamond report, most customers can locate the crystals by themselves. However, it’s highly recommended to inspect the imperfections in the actual stone using a diamond loupe or online 360-degree high-resolution imagery. Because their existence and the clarity grade cannot be quantified to actual impact on the diamond’s visual appearance or beauty—as a diamond is graded under a controlled lighting environment (darkfield illumination and sometimes brightfield) while we observe the gem under natural lighting conditions.

The vivid brilliance, fire and sparkle of brilliant cut diamonds can help distract you from the crystal inclusions. Conversely, if you prefer a step-cut gem, such as emerald cut diamond, you'd better upgrade the clarity grade to minimize the potential negative impact of crystals since the "hall of mirrors" effect of emerald diamonds is not skilled at disguising inclusions.