Rocks can best be identified by their
hardness
mineral content
color
grain

Rocks can best be identified by their mineral content. This is because rocks are composed of one or multiple numbers of minerals. Quartz, calcite, feldspars, and micas are examples of minerals that make rock formations possible.

Rocks are the basic component of the Earth's crust. Mountains, hills, and volcanoes are examples of rock formations that occur through time on Earth. One can find rocks all over the Earth and most are usually under the soil. Rocks can be further classified as igneous, sedimentary, or metamorphic rocks.