Crystal/ mineral inclusions
Some diamonds show the presence of small crystals, minerals or other diamonds. These are classified in various categories depending upon the size and structure of the inclusion. While many such inclusions are small in size and not visible to the naked eye, some diamonds may have large inclusions, which can be seen with the naked eye and can affect a diamond’s clarity and also its life. Some crystals resemble a diamond inside a diamond and may also add to the look of the stone. These take on shapes of bubbles, needles or grains and are classified as under
As the name implies, these inclusions are minute crystals usually white in color present inside the diamond. These resemble a small point of light and are, by far, the most common of all flaws found in diamonds. Most pinpoint inclusions do not affect the clarity of a diamond and are not visible to the naked eye and are usually not indicated on the plotting diagrams of diamond reports. Comments such as pinpoints not shown may be listed in the comments section.
Diamond crystals in a diamond can also be present in the form of long and thin needles. These may not be visible to the naked eye, unless the needle inclusion is of a noticeable color or has a noticeable presence. Some needle inclusions are known to give diamonds a special look too.
The presence of three or more pinpoint inclusions close together can create an area of haze or a cloud in the diamond. While the occurrence of a small cloud is not visible to the naked eye, presence of many pinpoints covering a large area can affect the clarity of the diamond. These are usually indicated on grading reports in the form of tiny red dots close together or as circles and other formations.
When diamond crystals extend to the surface of the diamond, they are referred to as knots. These can be viewed under proper lighting conditions with a diamond loupe. Certain knot formations may also cause raised areas on particular facets of the diamond. The presence of knots may affect both the clarity and durability of the diamond and are best avoided.
Crystal inclusions in diamonds can also occur in the form of lines, known as grain lines. These are usually formed due to improper crystallization of the diamond, when it was being formed. Grain lines can also be caused due to improper polishing of the diamond. Even skilled diamond cutters may come across diamonds with variations in hardness when a facet is polished. This can cause microscopic lines across the facet. These grains are usually difficult to remove without excessive weight loss. Grain lines are commonly seen in pink fancy diamonds. A saturation of grain lines on pink stones can also make them look red.
These are cracks in the stone that resemble the design of feathers. Presence of this in a diamond usually does not affect the life of the stone unless and until the feather runs through a major length of the stone or shows major stress points where it can break. If the cracks reach the surface or have deep fissures, the durability of the stone may be reduced with the possibility of the stone breaking with age.
Twinning wisps or intergrowths may also be seen in diamonds. These formations are usually inclusions in diamonds that have twisted together during the time of diamond formation. Thus various inclusions like pinpoints, needles or feathers may form together creating a white strip inside the diamond. Surface graining may also be seen in some cases. Such intergrowths are more commonly seen in fancy shaped diamonds and are extremely rare in ideal cut diamonds.
These are cracks in a diamond that occur in a straight line and are parallel to one of the diamond’s crystallographic planes. Cleavages are usually caused by deep internal strain in a diamond and could also have been caused by a strong blow on the diamond. It usually shows no feathers and has a great chance of causing the stone to split, especially if placed in the high pressure grip of prongs in rings. Stones with cleavage must be chosen carefully and avoided as far as possible.
Also known as girdle fencing or ‘dig marks’, this is caused around the diamond’s girdle as the diamond is cut or bruited. These fine lines usually resemble a hair strand and do not present a problem. However extensive bearding can lessen the brightness of the diamond. It is suitable that such diamonds be cut or polished again to improve luster.
Diamond flaws are not always a negative phrase. In fact it is these flaws that often lend a loose diamond its distinctive beauty. It is often these flaws that make a stone look unique and often raise its value much further. It is however necessary that while purchasing individual diamonds, the buyer examines them with a jeweler’s magnifier to check its brilliance and the presence of flaws. Careful considerations will go a long way in helping you buy a stone that remains precious, beautiful and unique for a lifetime.