Inclusion

Gem Identification

Definition

Any material enclosed within a gemstone during its formation, including crystals of other minerals, fluid-filled cavities, fractures, needles, or growth features.

Detailed Explanation

Inclusions are the 'fingerprints' of natural gems and are indispensable for gemological identification. A ruby containing rutile silk needles (intersecting at 60°) indicates corundum crystallized in the trigonal system. Emeralds contain a characteristic three-phase inclusion (solid crystal + liquid + gas bubble in the same cavity) called a jardin, from the French for 'garden.' Inclusions can also identify geographic origin — Burmese rubies often contain calcite crystals, while Thai rubies commonly show iron-rich rutile. Unlike diamonds, colored gem inclusions are generally accepted by the trade as long as they don't threaten durability.

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