Multiple choice general knowledge science & technology

Which of the following substances is the hardest?

  1. Graphite

  2. Talc

  3. Daimond

  4. Calcite
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Diamond is the hardest known natural material on the Mohs scale of mineral hardness (10 out of 10). Graphite is soft and used in pencils, talc is the softest mineral (1 on Mohs scale), and calcite has a hardness of 3. Diamond's hardness comes from its strong covalent bonds between carbon atoms.

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