Rocks are primarily composed of:

Rocks are primarily composed of one or more minerals, which is the foundational concept in the study of geology. Minerals are naturally occurring inorganic substances with a specific chemical composition and ordered atomic structure. This variety means that rocks can be made up of a single mineral, such as limestone made primarily of calcite, or a composite of multiple minerals, such as granite, which consists of quartz, feldspar, and mica among others.

The formation of rocks involves geological processes such as cooling and solidification of magma (igneous rocks), compaction and cementation of sediments (sedimentary rocks), or alteration due to heat and pressure (metamorphic rocks). Given this understanding of rock classification and composition, the assertion that rocks are composed of one or more minerals accurately encompasses the essential properties that define rocks and their significance within the earth's crust.