In mineralogy, which mineral is considered the softest on the Mohs hardness scale?

• A. Quartz
• B. Calcite
• C. Talc
• D. Gypsum

Answer: (C)

Verified step by step guidance

1. Understand that the Mohs hardness scale is a qualitative ordinal scale characterizing the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.
2. Recall that the scale ranges from 1 to 10, where 1 represents the softest mineral and 10 the hardest.
3. Identify the minerals listed in the problem: Quartz, Calcite, Talc, and Gypsum.
4. Know that Talc is assigned the value 1 on the Mohs hardness scale, making it the softest mineral.
5. Recognize that Quartz, Calcite, and Gypsum have higher hardness values (Quartz is 7, Calcite is 3, and Gypsum is 2), so they are harder than Talc.