Rocks and Minerals: Understanding the Difference

Rocks vs Minerals

• Rocks are different from minerals, but both are solids and can be found in the earth's crust.
• A mineral is a naturally occurring substance with unique chemical and physical properties.
• Minerals are inorganic, multicolored, have a specific structure, and are defined by their chemical composition.

Mineral Definition

• A mineral is a solid with a crystalline internal structure that occurs naturally.
• Minerals can be made from multiple types of elements or just one.
• Minerals have a definite crystalline structure and can have nutritional value.

Classifying Minerals

• Minerals are classified by their chemical composition and crystalline structure.
• Other ways to characterize minerals include examining the color, density, hardness, streak, luster, and solubility.
• Geologists classify crystal structures by the number of sides, angles, cleavage, and fracture.
• There are three main types of crystalline structures: Body-Centered Cubic (BCC), Hexagonal Close-Packed (HCP), and Cubic Close-Packed (CCP).

Rock Definition

• A rock is a solid interconnected collective of one or more crystalline minerals.
• Rocks are usually made up of various types of mineral grains, held together in one solid form.
• The study of rocks is called petrology.

Classifying Rocks

• Rocks are classified based on how they are formed.
• There are three main rock classifications: igneous, sedimentary, and metamorphic.
• Igneous rocks are made from hot magma that cools to create rock.
• Sedimentary rocks are made over time by pressure from other rocks.
• Metamorphic rocks are made from other rocks through chemical reactions and heat.

Rock Cycle

• The rock cycle is the process in which all rock is made or recycled.
• Igneous rocks can become sedimentary rocks through weathering, sedimentation, and lithification.
• Sedimentary rocks can become metamorphic rocks through heat and pressure, deformation, and recrystallization.
• Metamorphic rocks can become igneous rocks through melting and crystallization.

Comparing Rocks and Minerals

• Rocks are not minerals, and minerals do not always make rocks.
• Most rocks are made of minerals, but some rocks have no minerals.
• Rocks can have fossils, but minerals do not.
• Rocks can have varied colors, while minerals have specific colors.

Learn about the key characteristics that distinguish rocks from minerals, including their composition, structure, and properties.