Inclusions are clarity imperfections located within a diamond. The overwhelming majority of diamonds have some degree of inclusions, with less than .0001% of all mined diamonds being truly flawless.
There are many different types of inclusions, and they can have varying effects on a diamond’s appearance. There are however, certain types of inclusions which have the potential to severely impact a diamond’s appearance or structure, even when present in limited quantities. You should avoid purchasing diamonds with prominent inclusions that fall into this category.
Carbon Crystals – Carbon is the material from which diamonds form. During this formation process, small pockets of carbon may remain in their initial state. This will result in a black spot within the diamond’s structure. These spots can stand out and may detract from the visual appeal of the stone. This is especially true if they are large, numerous or centrally located.
Only lower clarity diamonds in the Slightly Included (SI) or Included (I) grades will exhibit noticeable carbon crystals. If you are looking for a diamond within these clarity grades, you should be aware that they may have noticeable black spots, and avoid them if possible. In the case of Diamonds of the I1 or lower grades, black spots are usually unavoidable and you should instead focus on finding a diamond with carbon crystals on the sides (less noticeable), rather than in the center.
Cleavages – Cleavages are breaks within a diamond. These are usually perceived as lines, and can have a feathered appearance. While these breaks can come in varying sizes, when the break runs from the middle of the stone all the way to its surface, it can present an issue. This form of cleavage is dangerous because it can jeopardize the diamond’s internal structure, resulting in vulnerability to stress. When put under pressure or knocked, the diamond may be susceptible to breaking or chipping along the cleavage line.
Unless you are purchasing a near flawless stone, your diamond will almost certainly have some degree of inclusions. These are natural to a diamond’s structure. As long as you avoid the extreme cases mentioned above, the inclusions should not have a large effect on the appearance or durability of your diamond.