What term describes a fracture-related color phenomenon observed when the diamond is viewed parallel to filled inclusions and rocked?

What term describes a fracture-related color phenomenon observed when the diamond is viewed parallel to filled inclusions and rocked?

• A. Fracture filling
• B. Flash effect
• C. Foilback
• D. Foss

Answer: (B)

The flash effect is a fracture-related color phenomenon that shows up when a diamond containing filled fractures is viewed parallel to those filled inclusions and then rocked. The filled cracks act like tiny prisms or optical guides. As you tilt and rotate the diamond, light traveling through or along these fracture planes is refracted and dispersed differently, producing brief bursts of color. This is a dynamic visual effect tied to the interaction between light and the filled fracture surfaces, rather than a static feature of the diamond’s color itself. Fracture filling describes the process of sealing cracks with a material, which is not about producing color flashes; the other terms don’t describe this light-dispersion phenomenon.

The flash effect is a fracture-related color phenomenon that shows up when a diamond containing filled fractures is viewed parallel to those filled inclusions and then rocked. The filled cracks act like tiny prisms or optical guides. As you tilt and rotate the diamond, light traveling through or along these fracture planes is refracted and dispersed differently, producing brief bursts of color. This is a dynamic visual effect tied to the interaction between light and the filled fracture surfaces, rather than a static feature of the diamond’s color itself. Fracture filling describes the process of sealing cracks with a material, which is not about producing color flashes; the other terms don’t describe this light-dispersion phenomenon.