Lustre refers to which property of a substance?

• A. Shine or reflective quality of a substance
• B. Color of a substance
• C. Texture of a surface
• D. Hardness of a material

Answer: (A)

Lustre describes how shiny a substance looks, essentially its reflective quality. A surface with high lustre reflects light in a smooth, bright way, like polished silver or a mirror. A surface with low lustre appears dull because it scatters light rather than reflecting it cleanly. This is distinct from color, which depends on the wavelengths of light reflected; texture, which is about roughness or smoothness; and hardness, which is about resistance to scratching. So the shine or reflective quality best captures the concept of lustre.