Which term describes a flat, triangular twinned diamond crystal?

Which term describes a flat, triangular twinned diamond crystal?

• A. Grain lines
• B. Habit
• C. Singly refractive (isotropic)
• D. Macle

Answer: (D)

A maclé is a flat, triangular twinned diamond crystal. It forms when two diamond crystals grow together in a twin orientation along a common plane, producing a flat, triangular (often rhomboidal) outline. This specific shape is distinct from other crystal descriptors: habit refers to the overall crystal form, not the result of twinning; grain lines are internal growth features; singly refractive (isotropic) describes how light travels through the mineral, not its shape. So maclé is the term that captures that flat, triangular twinned form.

A maclé is a flat, triangular twinned diamond crystal. It forms when two diamond crystals grow together in a twin orientation along a common plane, producing a flat, triangular (often rhomboidal) outline. This specific shape is distinct from other crystal descriptors: habit refers to the overall crystal form, not the result of twinning; grain lines are internal growth features; singly refractive (isotropic) describes how light travels through the mineral, not its shape. So maclé is the term that captures that flat, triangular twinned form.