Gemstone Inclusions - Beauty Beneath the Surface

Gemstones come in a wide variety of sizes, shapes, colors, and have their unique chemical properties and visual or scientific phenomena. One major element that plays a part in defining a mineral or a crystal, especially with quality, is the inclusion.

What are Mineral or Gemstone Inclusions?

The most common definition for a mineral inclusion would be an extrinsic or foreign object or material enclosed within the the mineral. This can be a rather broad definition, since it could be any other mineral stuck inside the stone, as is usually the case, like with yellow aventurine and its inclusions of mica or muscovite. But it doesn't have to be. In fact, enhydro agate is said to have inclusions of water. Some of the most famous, however, has to be amber's inclusions of insects and plant matter.

How do Inclusions Happen?

Inclusions are virtually always natural. In order for an inclusion to be present, it has to have been there since the formation of the stone. As such, according to the natural laws of inclusions from James Hutton, these inclusions have to be older than the main stone itself.

Above: Amber with insects and spider. Not for sale. By definition, they would be inclusions.

They become a part of the natural formation during the growth or creation of a crystal, which generally happens over a very long period of time. As minerals build, sometimes foreign particles can get trapped inside. And as it continues to grow, it gets trapped inside. Again, this process can take a very long time. 

Do Inclusions Reduce Gemstone Value?

This depends heavily on the kind of gemstone or mineral. Some people like inclusions in their minerals, such as included quartz or star sapphire. Sapphire that displays asterism is usually from inclusions. Many stones have inclusions and finding one that has none or very few can be a challenge; this is especially true for colored gemstones, and some of which are dependent on inclusions for different variants.

Image above - Star Sapphire Displaying Asterism from inclusions. Not for sale.

Other stones, however, have extremely high values when they are said to be inclusion free. The most famous example is the diamond. A diamond with inclusions is said to have lower clarity and is thus of a lower value.

Inclusions, regardless of the perceived value, are actually important to mineralogists and gemologists who study the history, age, formation, chemical composition, and varieties of the main mineral. In short, they can tell mineralogists a lot and are too frequently discounted by people who value only aesthetics of a stone.

The Wrap Up

Inclusions are valuable in more ways than one. Some of them add unique and pretty properties to stones, and others are a natural part of their hue and formation. Inclusions are old, but they should not be forgotten or ignored. They play a far greater role in gemstones than most people think!

Sources:

https://www.gia.edu/gems-gemology/summer-2022-colored-stones-unearthed