What is the term for the process of rubbing leather-hard or dry clay with a smooth tool to polish and tighten the surface?

• A. Polishing
• B. Smoothing
• C. Hardening
• D. Burnishing

Answer: (D)

Burnishing is the technique of rubbing a smooth tool over leather-hard or dry clay to compress and seal the surface, creating a tighter, polished look. The friction smooths the clay surface and reduces porosity, so a sheen develops as the surface fuses slightly under pressure. Doing this on leather-hard or dry clay is ideal because the material holds its shape while you work, and the resulting polished surface fires cleanly.

While polishing or smoothing describe surface work in a general sense, burnishing specifically refers to this rubbing action with a smooth tool to tighten and shine the surface before firing. Hardening isn’t the term for this technique, since it doesn’t capture the polishing and sealing effect that burnishing achieves.