Question

Which of the following is NOT an organically formed rock?

Options

• Gypsum

• Peat

• Chalk

• Limestone

Answer 1

Gypsum

Explanation:

Gypsum is a chemically formed sedimentary rock, not an organically formed rock. Gypsum forms from the evaporation of mineral-rich water, leading to the precipitation of calcium sulphate. In contrast, peat, chalk, and limestone (when formed from shells and skeletons of marine organisms) are organically formed rocks because they originate from the accumulation and compaction of plant or animal remains. Therefore, gypsum is the correct choice, as it is not formed from organic material.