A way to identify a mineral that tells us what can scratch it is called?

• A. Luster
• B. Streak
• C. Color
• D. Hardness

Answer: (D)

Hardness is the property that describes how resistant a mineral is to being scratched. When you ask what can scratch a mineral, you’re looking at its scratch resistance, which is what hardness measures. Using a scratch test with substances of known hardness (like common minerals or materials) lets you compare and place the mineral on a relative scale. If it can scratch a material with a given hardness, it is harder than that material; if it’s scratched by a material with higher hardness, it’s softer. This is precisely what hardness tells you. Luster, color, and streak describe other properties—how light reflects, the color of the powder, and the color of the mineral itself—not its resistance to scratching.