Identifying Inclusions of Specific Gems


Step 2: Advanced Gemology

Lesson 12

Beryl and Tourmaline

Both beryl and tourmaline develop hollow, or “growth” tubes. The gem cutter sees many more of these than the gemologist does, as most are cut away. While they begin hollow, the tubes may later be filled with opaque, white minerals.

Growth tubes are easy to distinguish from other inclusions. Their sides are even and they run straight for a considerable distance. When these inclusions are present, you can assume that the gem is most likely a beryl, tourmaline, or possibly a spodumene. The refractive index will separate these minerals.

Corundum

Rubies and sapphires are …

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