Types of Diamond Inclusions & Blemishes Explained with Pictures

When you see a diamond report that indicates the presence of beards in a diamond, please do not take the literal meaning. Bearding is an inclusion that occurs when cutting the stone. Diamond cutting or bruting is a rigorous process that involves heating and grinding the rough diamond crystal. As a result, many tiny strands of hair appear around the diamond’s girdle, hence the term bearding. It is worth noting that the hair-like inclusions only arise out of an improper bruting process. It is a situation that can happen when the cutter is unskilled or lacks experience using cutting equipment. Bearding along the girdle of a diamond is relatively easy to spot on an enlarged diamond image.

A small presence of hairs or beards does not affect the stone’s luster much. Conversely, a heavily bearded diamond girdle has dark-greyish furs that affect the stone’s clarity grade. They could result in an SI2 grading when easily visible under 10x magnification. Other terms that gemologists use for this type of inclusion are girdle fencing, girdle fringes, and dig marks. You might come across the two phrases in diamond reports (depending on the grading agency) and different diamond industry publications.

Diamonds form deep within the Earth's surface, well into the inner layers of the mantle, at depths exceeding 100 miles beneath sea level. Temperatures can soar to around 2000 degrees Fahrenheit, and pressures can reach up to 70,000 pounds per square inch. Such extreme conditions inevitably give rise to imperfections both within and on the surface of a diamond. Diamonds are renowned for being the hardest mineral on the Mohs hardness scale, boasting a perfect hardness rating of 10.

These conditions are also optimal for their crystallization. Alongside diamonds, other minerals and crystals also come into being. It's common for these minerals to become ensnared within a larger diamond during its formation. Foreign minerals that may be found within a larger diamond include reddish crystals, such as garnets, or greenish ones, predominantly peridot. Additionally, minute minerals or crystals, such as iron oxide, silica, diopside, calcite, and spinel, can become embedded within a diamond stone. There's even the possibility of smaller diamond crystals being encapsulated within a stone. In such cases, gemologists refer to them as "baby diamonds."

Colored minerals typically don't pose a significant threat to the overall clarity of the stone, particularly when present in minute quantities or scattered across the stone's body. However, a concentration of minerals in a single area can easily become noticeable under 10x magnification or may even be visible to the naked eye. Such occurrences are not favorable in terms of the stone's clarity grade.

In instances involving baby diamonds, various interpretations can arise based on the nature of the trapped diamond crystal. These baby diamonds can adopt fanciful shapes that enhance the beauty and distinctiveness of the stone. Gemologists have occasionally come across baby diamonds resembling shapes like dragons, bumblebees, dolphins, and even hearts. In such extraordinary cases, regardless of whether the crystal is white, colorless, or colored, it's considered an additional gemstone—a two-for-one deal, so to speak. Baby diamonds and foreign crystals can also manifest as needle-like formations, pinpoints, or clouds. Each of these captivating shapes, in and of itself, is classified as an inclusion.

Crystals within a diamond that take on a long and slender appearance are commonly called "needles." While these needles might be transparent and only discernible through images magnified with a jeweler's loupe, their presence often indicates a diamond of at least SI1 clarity. However, suppose a colored needle crystal is sufficiently large or near the surface. In that case, it might become visible to the naked eye through the diamond's table, crown, or pavilion.

Regardless of size or color, needle or small rod-shaped crystals can vary in appearance. Some are white, elongated, and clustered in a specific area, making them easily noticeable even to an untrained observer. In such cases, using a loupe or microscope is unnecessary; these characteristics are generally found in diamonds falling within the clarity range of SI2-I3. Diamonds with this level of clarity can be problematic, as many jewelers avoid carrying I2 and I3 graded stones due to their reduced quality.

A pinpoint is a type of crystal that could have a white or dark (black coloration). Pinpoints are among the most common inclusions in almost all types of natural diamonds. They share that commonality with needles and feathers. Typically, a single pinpoint is so tiny that it is regarded as smaller than a speck of dust. Being tinier than dust particles means that a GIA-certified professional finds it difficult to identify a pinpoint even under 10x.

It is only possible to locate the smallest pinpoints under higher magnification, say 30x or 40x. Such a case warrants a "pinpoints not shown" or "clouds not shown" comment on the diamond certificate. It means pinpoints are present but only visible under a magnification beyond the industry standard (10x). Pinpoints on the clarity plot of your diamond’s certificate should be the least of your clarity concerns. The presence of a cluster of pinpoints or larger dark-colored pinpoints should make you a bit uneasy.

A significant concentration of white pinpoints creates a fuzzy dot in that area of the stone. The cloudy appearance hinders the traveling of light in the stone. A cloud in the crown of the stone stops light from piercing through the girdle and into the pavilion. Consequently, reflection and brilliance are affected. A grouping of closely-positioned pinpoints is called a cloud—an inclusion.

On the other hand, dark pinpoints indicate the presence of carbon or graphite crystals in the stone. Dark spots are harmless when unnoticeable to the naked eye. Darker and stark black spots in the middle of a diamond’s table are the worst. They are visible to the unaided eye, especially on a large table, in step-cut stones such as emerald and Asscher.

It is better to have a dark-toned spot far off the side of the stone, away from the girdle and the surface. An excellent cut in the round and princess cuts can do a great job of hiding black spots. The lightly dark spots in the pavilion and the edge of the diamond in contact with a metal setting are concealable with a prong setting.

If a GIA report's comment section states "clarity grade is based clouds", avoid the diamond unless it is a VVS/VS1 clarity grade.

Feathers derive their name from their resemblance to bird feathers. "Feather" is a comprehensive term used by GIA and AGS to encompass all types of cracks (fissures), fractures, and breaks occurring within a diamond. Despite being a relatively common imperfection, feathers can have an impact on the structural integrity of the stone.

When small, particularly in SI1 diamonds or higher, feathers remain invisible to the naked eye and require magnification for detection. Their feathery appearance, inconspicuous location, and colorless nature make them benign inclusions. However, depending on the angle of observation, a crack or fracture might reflect light and exhibit an unsightly opaque aspect.

A significant fracture positioned close to the surface or near the stone's girdle should raise concerns. Certain feathers can be substantial and extend over a significant distance. This means a feather might originate in the crown and extend through the girdle, reaching well into the lower portion of the stone. Such a feather loses its aesthetic appeal, lowers the stone's clarity ranking, and poses a risk. In I1 grade diamonds, these feathers are visible to the naked eye, both when the stone is viewed face-up or face-down. The GIA clarity plot typically takes note of such internal flaws.

If a feather breaches the girdle, it raises doubts about the diamond's durability and increases the likelihood of breakage over time. The risk intensifies if the feather displays areas of stress or is situated adjacent to included crystals. Tension could cause the crack to widen further, creating a cleavage plane.

This situation becomes even more perilous when the cleavage plane forms a straight line or runs parallel to one of the stone's crystallographic planes. An accidental impact on the stone would inevitably result in breakage. Moreover, if the feather is located on the girdle, pressure from a tension setting could cause the diamond to shatter. An extensive feather is an inclusion that should be avoided at all costs, as it presents a recipe for disaster.

GIA distinguishes between these internal irregularities, even though they share numerous similarities and can appear nearly identical to non-professional graders. They manifest in closely related ways. A "Cavity" refers to the hollow space left behind after an included mineral is extracted, either accidentally or intentionally, during the polishing process. For this inclusion to occur, the included crystal must be situated near the stone's surface, making it susceptible to disruption by a polishing wheel. Gemologists often refer to these included crystals as "knots," drawing an analogy to knots found in wood. These white or transparent crystals are partially embedded within the body of the stone.

In rare instances, a knot can cause the facet directly above it to appear slightly raised, creating the illusion of a protrusion compared to the surrounding facets. When the knot is removed, it leaves behind a depression—a cavity. Another type of opening, shallower than a cavity, is a "chip." A chip emerges on the surface of the stone as a result of a sharp blow that inflicts damage. The presence of a different inclusion might precede the formation of a chip.

A prime example involves the presence of feathers near the edges of the stone, within the girdle, at facet intersections, or even at the culet. Similarly, "bruises" are often found at facet junctions, particularly on the crown. Bruises can develop when a diamond comes into contact with rough materials or experiences a forceful impact against a hard surface. In some cases, feathers might arise from the same forceful impact that caused the bruise. To safeguard your diamond from this inclusion and the potential cascade of other clarity issues, it's crucial to take proper care of it.

You are already familiar with the extreme conditions under which diamonds form, as well as the prolonged duration of this process, which can span hundreds of thousands or even millions of years. It's worth noting that this formation process can be disrupted by shifts in underground temperatures or pressure levels.

In cases where such interruptions occur, diamonds can develop irregularly, leading to uneven crystallization. During this process, diamond wisps and graining may emerge. The uneven growth can result in twinning wisps, which fundamentally distort the crystallographic planes within the diamond. This manifests as a growth defect in the stone's crystal structure, composed of a series of overlapping pinpoints, clouds, crystals, and feathers.

These particular diamonds are referred to as "macle diamonds" by scientists. They often feature fancy cuts such as modified brilliant, step, mixed, rose, and mogul cuts, which are strategically employed to navigate around the wisps and intergrowth. The abnormal formation may also give rise to a graining effect, observable both within the stone (internal graining) and closer to its surface (surface graining).

Graining manifests as reflective, whitish, or colored lines situated deep within the stone's body (internal graining) or nearer to its surface (surface graining). Graining is discernible only under 10x magnification and has minimal impact on a diamond's clarity. In instances where graining is the sole "concern," the diamond can readily pass as internally flawless, showcasing no visible flaws.

The human mind continually seeks innovation, often leading to a juxtaposition of natural phenomena and technology. In the realm of the diamond industry, discussions surrounding diamond clarity enhancement technology have sparked controversy. While certain segments of diamond dealers endorse it, others harbor reservations.

Gemologists hold divergent perspectives on etch channels, categorizing them as either natural or human-made. It's essential to recall that diamonds originate within the Earth's mantle but must traverse to the crust for extraction. During this journey, the interaction with heat and friction against other rocks can result in the scraping of the diamond's surface. This scraping process produces faintly hollow tunnels, parallel or spiraling lines, which resemble scars or natural etch channels.

The utilization of laser cutting tools can also lead to marks, akin to manufacturing remnants, remaining on the diamond's surface. In certain instances, these mechanical marks may appear as white or milky lines under 10x magnification. Consequently, some assessors may interpret them as human-made etch channels. However, due to the precision of laser beams, these lines are only discernible to those with extraordinarily sharp vision. This circumstance is why the GIA might annotate the certificate with remarks such as "manufacturing remnants not shown."

Similarly, clarity enhancement might encompass the use of laser beams to drill holes that penetrate to the location of a dark crystal. Subsequently, a bleaching agent like sulfuric acid may be employed to lighten the crystal for achieving tonal color balance. The drill hole itself is regarded as an inclusion. Occasionally, technicians engaged in clarity enhancement might fill these holes with halogen-based glasses. An example of such a colorless substance is lead-bismuth oxychloride glass, which maintains a transparent appearance and tactile quality.

Whether these drill holes are concealed or not, they remain minuscule and imperceptible to the naked eye. Even individuals with exceptional eyesight cannot detect them without 10x magnification, elucidating the rationale behind certificate annotations such as "Internal laser drilling present." To ensure buyer protection, the GIA mandates that gemologists and jewelers disclose clarity enhancement procedures.

Certain inclusions can be tolerated, but it's advisable to steer clear of flaws. Isolated pinpoints and indented naturals (portions of the rough diamond beneath the stone's surface) are not indicative of an I clarity grade. To ensure clarity accuracy, rely on GIA or AGS comprehensive diamond reports and avoid unwelcome surprises. Be cautious of some jewelers who may label I1 diamonds as SI3 in clarity. It's important to note that the GIA does not recognize an SI3 grade on its clarity scale, so be wary of this marketing tactic.

According to Blue Nile, an online jeweler, SI1 and SI2 diamonds offer the best clarity value. However, be aware that SI1 inclusions might occasionally be visible to keen observers without requiring image enhancement. In the case of SI2 diamonds, inclusions can be seen through the table and pavilion under 10x magnification. Consider this information when making your selection.

Severe inclusions can impact the beauty, brilliance, and overall quality of your diamond. To avoid such issues, opting for VS clarity is recommended. Among VS clarity options, VS1 is superior to VS2. Instead of investing more in a VVS diamond, you might want to follow the lead of 43 percent of diamond buyers and opt for a VS1 stone. These stones are typically guaranteed to be eye-clean and offer excellent value for your investment.