Which term describes the appearance of a material's surface in reflected light?

Which term describes the appearance of a material's surface in reflected light?

• A. Luster
• B. Length-to-width ratio
• C. Lower girdle facet percentage
• D. Macle

Answer: (A)

Luster describes how a surface looks in reflected light. A smooth, well-polished diamond surface reflects light with brightness and shininess, often described as adamantine luster. This focuses on the surface’s gleam and how light interacts with it, which is exactly what “appearance in reflected light” means. The length-to-width ratio is about the diamond’s shape and silhouette, not its surface brightness. The lower girdle facet percentage relates to how many facets surround the girdle and how they’re arranged, which affects light performance but not the basic description of surface reflectivity. A macle refers to a crystal formation within the diamond, a structural feature rather than the surface’s reflective appearance.

Luster describes how a surface looks in reflected light. A smooth, well-polished diamond surface reflects light with brightness and shininess, often described as adamantine luster. This focuses on the surface’s gleam and how light interacts with it, which is exactly what “appearance in reflected light” means.

The length-to-width ratio is about the diamond’s shape and silhouette, not its surface brightness. The lower girdle facet percentage relates to how many facets surround the girdle and how they’re arranged, which affects light performance but not the basic description of surface reflectivity. A macle refers to a crystal formation within the diamond, a structural feature rather than the surface’s reflective appearance.