Inclusion

Inclusions are by definition any material trapped within a mineral during its formation, such as atmospheric gas, liquids, or even insects.

Whether an inclusion is desirable or undesirable depends a great deal on the mineral, amount of included material, and sometimes even the arrangement of the material, such as how a insect is trapped in amber. The type and amount of inclusions can be the biggest determining factor in evaluating a gemstones clarity.

However, inclusions should not be confused with blemishes; the characteristic difference between the two are that inclusions originate from within the stone, whereas Blemishes generally confined to the surface of a gemstone.

Inclusions in diamonds can negatively impact their value a great deal as the the brilliance and sparkle depend on inclusion-free material in addition to proper cut.

On the other hand, inclusions in emeralds are often considered desirable because of the aesthetic effect it gives to the gemstone. In fact, inclusion-free emeralds are so rare that to discover one often makes the gemstone immediately suspect as synthetic?.

The two most common forms of inclusions found in emeralds are fissures and fluid filled cavities, as described below:

• Fissures, commonly referred to as 'feathers', occur naturally in the mineral and permeate the throughout the gemstone. They are almost ubiquitous with regard to emeralds and are generally considered undesirable only if excessive in amount or somehow effect the stones durability.

• Fluid filled cavities usually consist of a salty liquid and/or gas bubbles. These types of inclusions can be further categorized into single-phase, two-phase, or three-phase, depending on the materials contained within the inclusion. In this sense, inclusions can be extremely helpful in determining the origin of a gemstone. As an example, Colombian emeralds are noted for jagged-edged three-phase inclusions consisting of a liquid, gas bubbles, and halite salt.

Occasionally, other growth structures will be present such as pyrite or carbon.