Earth materials and minerals — hardest material among the choices Which of the following is the hardest material listed?

Introduction / Context:
Hardness is a material’s resistance to scratching or indentation. In geology and materials engineering, the Mohs scale is commonly referenced for minerals, while engineers often consider absolute hardness for wear applications. Identifying the hardest among common materials helps in tool selection and wear design.

Given Data / Assumptions:

• Diamond is a mineral with Mohs hardness of 10.
• Quartz has Mohs hardness of about 7; marble (calcite-based) around 3; talc is the softest at 1.
• The list mixes minerals (diamond, talc, quartz) and rocks (marble).

Concept / Approach:
On the Mohs scale, diamond defines the maximum hardness and can scratch all other listed materials. Although the question says “rock,” the options include minerals; in standard exam convention, diamond is taken as the hardest among the given choices.

Step-by-Step Solution:
Compare Mohs hardness values: diamond 10 > quartz 7 > marble (calcite ~3) > talc 1.Select the maximum hardness entry: diamond.Therefore, the hardest listed material is diamond.

Verification / Alternative check:
Industrial practices use diamond abrasives for cutting and polishing hard rocks and metals; no other listed material can scratch diamond.

Why Other Options Are Wrong:
Quartz is hard but far below diamond; marble is relatively soft; talc is the softest standard mineral.

Common Pitfalls:
Confusing rock names with mineral hardness; assuming granite (not listed in options here but common) is harder than quartz—it is an aggregate rock containing quartz and feldspar; overlooking that Mohs is ordinal, not linear.

Final Answer:
Diamond