Cleavage plane is defined as ...

Cleavage plane is defined as ...

• A. Plane parallel to a possible crystal face, where a diamond can split cleanly when struck.
• B. A surface where diamonds are mounted for display.
• C. A fragile layer within the stone that causes yellowing.
• D. A tool used to polish facets.

Answer: (A)

Cleavage plane is a plane of weakness in the diamond’s crystal that allows it to split cleanly when struck, and this plane lies parallel to a possible crystal face. This orientation explains why diamonds tend to fracture along flat, specific directions—the crystal structure has planes where bonds are weaker, making clean splitting possible. This concept is essential for understanding how rough diamonds are cut and shaped, since cutters plan breaks along these planes to control the stone’s final form. The other ideas describe things like mounting surfaces, an internal layer causing yellowing, or a polishing tool, which don’t relate to how the crystal structure determines breakage.

Cleavage plane is a plane of weakness in the diamond’s crystal that allows it to split cleanly when struck, and this plane lies parallel to a possible crystal face. This orientation explains why diamonds tend to fracture along flat, specific directions—the crystal structure has planes where bonds are weaker, making clean splitting possible. This concept is essential for understanding how rough diamonds are cut and shaped, since cutters plan breaks along these planes to control the stone’s final form. The other ideas describe things like mounting surfaces, an internal layer causing yellowing, or a polishing tool, which don’t relate to how the crystal structure determines breakage.