What is the relationship between dispersion and visual 'fire' in gemstones, and how does it differ between diamond and moissanite?

• A. Higher dispersion yields more pronounced fire; moissanite has higher dispersion than diamond, so more fire.
• B. Dispersion has no effect on fire.
• C. Diamond has higher dispersion than moissanite.
• D. Moissanite is without any dispersion.

Answer: (A)

Dispersion is the splitting of white light into its spectral colors as it passes through a gemstone, producing the colorful flashes known as fire. The amount of fire you see depends on how strongly the material separates colors, i.e., its dispersion. Moissanite has a higher dispersion than diamond, so light is spread into colors more, resulting in more pronounced fire. While the cut, brightness, and lighting influence how noticeable the fire is, the underlying material property sets the potential: higher dispersion means more fire. That's why moissanite typically shows more vivid fire than diamond.