Chalk and marble are different forms of

Chalk and marble are different forms of

[amp_mcq option1=”Calcium hydrogen carbonate” option2=”Calcium carbonate” option3=”Calcium acetate” option4=”Sodium carbonate” correct=”option2″]

This question was previously asked in
UPSC NDA-2 – 2020
Chalk and marble are both naturally occurring forms of calcium carbonate (CaCO₃).
– Calcium carbonate is a common substance found in rocks as the minerals calcite and aragonite.
– Marble is a metamorphic rock composed primarily of recrystallized carbonate minerals, most commonly calcite.
– Chalk is a soft, white, porous sedimentary rock, a form of limestone composed primarily of the mineral calcite.
– While chemically the same (CaCO₃), chalk, limestone, and marble differ in their crystal structure, formation process, and physical properties like hardness and texture.
– Calcium carbonate is also the main component of shells of marine organisms, snails, and eggshells.