Inclusions Overview
Introduction to inclusions, their classification, and microscopy techniques for examination.
microscopy identification fundamentals
Introduction
Inclusions are internal features that provide valuable information about a gem's
identity, origin, and natural vs. synthetic status. They are a gem's "fingerprint."
Understanding inclusions is fundamental to gemmological identification. Each gemstone
species, and often each geographic origin, exhibits characteristic inclusion patterns
that aid in accurate identification.
Classification of Inclusions
Inclusions can be classified by their nature and timing of formation:
By Nature:
- Solid inclusions - Crystals of other minerals
- Fluid inclusions - Trapped liquids, gases, or combinations
- Growth features - Patterns from crystallization process
By Timing (Relative to Host Crystal):
- Protogenetic - Formed before the host crystal
- Syngenetic - Formed at the same time as the host
- Epigenetic - Formed after the host crystal
Microscopy Techniques
Different lighting techniques reveal different inclusion types:
- Darkfield - Best for seeing inclusions against dark background
- Brightfield - Good for colour zoning and growth patterns
- Fibre-optic - Pinpoint light for specific features
- Immersion - Reduces surface reflections, reveals internal features
- Polarized light - Shows strain patterns and twinning