Which term describes the crystal shape that is characteristic of a material, used to describe its habit?

Which term describes the crystal shape that is characteristic of a material, used to describe its habit?

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

Answer: (C)

Crystal habit is the shape a crystal tends to form as it grows, the external form that reflects its internal structure and growth conditions. The term used to describe this is habit. This is the best choice because it directly names the observable morphology—the characteristic crystal form—while the other terms refer to different ideas: grain lines are surface markings, optical properties like isotropy describe how light travels through the crystal, and trace elements are impurities that can influence color or other properties but not the crystal’s overall shape. In diamonds, for example, the classic well-formed habit is octahedral, illustrating this external form.

Crystal habit is the shape a crystal tends to form as it grows, the external form that reflects its internal structure and growth conditions. The term used to describe this is habit. This is the best choice because it directly names the observable morphology—the characteristic crystal form—while the other terms refer to different ideas: grain lines are surface markings, optical properties like isotropy describe how light travels through the crystal, and trace elements are impurities that can influence color or other properties but not the crystal’s overall shape. In diamonds, for example, the classic well-formed habit is octahedral, illustrating this external form.