Inclusion
Definition
Any material that is trapped inside a mineral during its formation. Inclusions can be other minerals, gas bubbles, or liquids.
Example
Rutilated quartz contains needle-like inclusions of the mineral rutile.
Nature's Fingerprints
An inclusion is any material that is trapped inside a mineral during its formation. To a gemologist, inclusions are not just "flaws"—they are a diary of the gemstone's history. They can identify the specific mine a stone came from or prove that a gem is natural rather than synthetic.
Types and Value
- Solid: Tiny crystals of other minerals (e.g., Pyrite crystals inside Lapis Lazuli).
- Liquid/Gas: Tiny bubbles or "two-phase" inclusions containing fluids.
- Value-Adding Inclusions: While inclusions usually lower clarity and value, some are prized. The "horsetail" inclusions in Demantoid Garnet increase its value, and the "silk" (rutile needles) in Sapphire creates the star effect (asterism).