Which property describes a material's resistance to penetration or scratching?

• A. Toughness
• B. Elasticity
• C. Hardness
• D. Ductility

Answer: (C)

Hardness is the property that describes a material’s resistance to penetration or scratching. It tells you how well the surface resists being dented or scratched by another material. Hardness is typically assessed with indentation or scratch tests, using scales such as Mohs for minerals or instruments that yield Vickers or Rockwell numbers. In practice, higher hardness means better resistance to wear from surface contact, which is why hard materials are chosen for cutting tools, dies, and protective coatings. However, hardness is different from toughness, elasticity, and ductility: toughness is about how much energy a material can absorb before fracturing, elasticity is about how well it springs back after deformation, and ductility is about how much it can be stretched into a wire. So when the question asks for a property describing resistance to penetration or scratching, hardness is the best match.