Which term refers to the following definition: The appearance of two images of facet junctions when viewed from the opposite side?

Which term refers to the following definition: The appearance of two images of facet junctions when viewed from the opposite side?

• A. Doubling
• B. Doubly refractive (anisotropic)
• C. Digging out
• D. Emplacement

Answer: (A)

This item tests recognizing a particular optical effect seen in a cut gemstone: the appearance of two images of a facet junction when you look at the gem from the opposite side. This effect is called doubling. It happens because light can travel multiple paths through the crystal and reflect off facets in such a way that the viewer sees a second, slightly offset image of where two facets meet. It’s a distinct observation from other optical phenomena. The term doubly refractive (anisotropic) refers to true birefringence, where a material splits light into two rays that travel at different speeds, producing two images under certain conditions. Diamonds are effectively isotropic, so this isn’t the phenomenon described here. Emplacement and digging out are unrelated terms in this context.

This item tests recognizing a particular optical effect seen in a cut gemstone: the appearance of two images of a facet junction when you look at the gem from the opposite side. This effect is called doubling. It happens because light can travel multiple paths through the crystal and reflect off facets in such a way that the viewer sees a second, slightly offset image of where two facets meet. It’s a distinct observation from other optical phenomena.

The term doubly refractive (anisotropic) refers to true birefringence, where a material splits light into two rays that travel at different speeds, producing two images under certain conditions. Diamonds are effectively isotropic, so this isn’t the phenomenon described here. Emplacement and digging out are unrelated terms in this context.