When treating gemstones, there are also efforts to remove inclusions. This is possible, for example, through a high-temperature treatment of rubies – at around 1,200 degrees, rutile, which often forms inclusions in rubies, begins to melt.

This kind of treatment may be carried out for aesthetic reasons, but from an investment point of view, the stone should be preserved in its natural state and therefore remain untreated.

Purity is one of the criteria for determining the value of gemstones. Especially with colorless gemstones, purity is important for determining the price. In addition to inclusions, flaws are also taken into account, i.e. superficial irregularities or changes that are not visible to the naked eye. The more devoided a gemstone is from inclusions, the purer it is:

For diamonds, there is a scale for evaluating clarity that begins with the highest level “flawless”, i.e. even under tenfold magnification, no inclusions within the gemstone are visible to the expert. The gradations go down to the lowest level “Piqué 3”, where large and/or numerous inclusions are present, which significantly reduce the brilliance.

Colored gemstones are roughly divided into three categories, from type I (eye-clean – e.g. blue topaz, aquamarine) to type II (mostly inclusions present – e.g. ruby) to type III (almost always inclusions – e.g. emerald). Colored gemstones are graded on a scale from “eye clean” to “severely included”. The demands made on the respective stone depend on the type to which it belongs, i.e. whether inclusions are to be expected or not.