The Difference between Rocks and Minerals

While both rocks and minerals are naturally occurring solid substances, there are key differences between them:

Mineral—A naturally occurring, homogeneous inorganic solid substance having a definite chemical composition and characteristic crystalline structure, color, and hardness. Minerals are chemical compounds. 

Rock—Relatively hard, naturally formed mineral or petrified matter; stone; a naturally formed aggregate of mineral matter constituting a significant part of the earth's crust. Rocks consist of one or more minerals.

Composition

Minerals: Have a definite chemical composition and a specific crystal structure. This means they are made up of specific elements in a specific arrangement. Examples include quartz, feldspar, and mica.

Rocks: Are aggregates of one or more minerals, or even other rock fragments. They don't have a fixed chemical composition or crystal structure. Examples include granite, sandstone, and marble.

Formation

Minerals: Form through natural processes like crystallization, precipitation, and biological activity. These processes can occur over long periods of time and under various conditions.

Rocks: Can form through various processes, including the cooling and solidification of magma (igneous rocks), the accumulation and compaction of sediments (sedimentary rocks), and the transformation of existing rocks under high pressure and temperature (metamorphic rocks).

Characteristics

Minerals: Generally have a uniform appearance and consistent properties like hardness, cleavage, and luster. They can be identified by these properties.

Rocks: Can have a wide range of appearances and properties depending on the minerals they contain and how they formed. They are identified based on their overall appearance and composition.