Which phenomenon explains the colored flashes seen in diamonds when light exits the stone?

• A. Dispersion
• B. Absorption
• C. Refraction
• D. Reflection

Answer: (B)

Dispersion is the split of white light into its spectral colors as it travels through a material whose refractive index varies with wavelength. In diamonds, light is forced to change direction many times inside the facets, and because the refractive index for red light differs from that for violet light, the different colors bend by different amounts. When the light exits the stone, these colors emerge at slightly different angles, producing the vivid colored flashes you see—diamond fire. Absorption would remove some wavelengths and tint the overall color, but it doesn’t create separate spectral flashes at exit. Refraction and reflection describe bending and bouncing of light but don’t inherently separate colors into a spectrum.