What are the characteristics of rock and how do you define them?

Rocks are defined by their mineral composition, texture, and formation processes. They can be classified into three main types: igneous, sedimentary, and metamorphic, each with distinct characteristics. Igneous rocks form from cooled magma or lava, sedimentary rocks consist of accumulated sediments and organic materials, and metamorphic rocks arise from the alteration of existing rocks under heat and pressure. Additional characteristics include color, hardness, and grain size, which help in identifying and classifying rocks.