Which term describes the appearance of double images of a gemstone facet junctions?

Which term describes the appearance of double images of a gemstone facet junctions?

• A. Crystal Shape
• B. Doubling
• C. Crystal Systems
• D. Glassie

Answer: (B)

Doubling is the term for the appearance of two images of a facet junction. When light travels through a gem and reflects off multiple facets, under certain angles you can see a ghost, offset image of the same junction. That offset, duplicated image is what we call doubling. It’s a specific optical effect tied to how light paths interact inside the stone, rather than the stone’s overall external shape or its mineral class. The other terms don’t describe this light-based duplication: crystal shape refers to the gem’s external form, crystal systems to the crystal lattice class, and the term that isn’t standard in gemology wouldn’t describe this phenomenon.

Doubling is the term for the appearance of two images of a facet junction. When light travels through a gem and reflects off multiple facets, under certain angles you can see a ghost, offset image of the same junction. That offset, duplicated image is what we call doubling. It’s a specific optical effect tied to how light paths interact inside the stone, rather than the stone’s overall external shape or its mineral class. The other terms don’t describe this light-based duplication: crystal shape refers to the gem’s external form, crystal systems to the crystal lattice class, and the term that isn’t standard in gemology wouldn’t describe this phenomenon.