Earth's Evolution
The process that formed and changed the Earth from its beginning to the present.
Mineral Composition
The unique combination of solid elements and compounds that make up a mineral.
Rock Cycle
Earth's rocks change from one type into another over time due to various Earth processes. Changes occur in mineral compositions and physical structures.
Igneous Rock
Igneous rock is formed when lava or magma cools and solidifies. Lava cools quickly and forms rocks with small crystals, while magma cools more slowly and forms rocks with larger crystals.
Lava
Molten rock or magma that has reached Earth's surface by volcanic action; characterized by small crystals due to rapid cooling on Earth's surface.
Magma
Melted or molten rock material beneath Earth's surface; cools slowly to form rocks with larger crystals.
Metamorphic Rock
Metamorphic rock is formed deep underground where heat and pressure cause existing rocks to be changed in both mineral composition and structural characteristics.
Heat and Pressure
Changing variables due to the weight of overlying rocks, causing changes to rock characteristics and mineral composition, thus forming metamorphic rocks.
Sedimentary Rock
Sedimentary rock forms when particles of other rocks are deposited in layers and are compacted (crushed together), and cemented (binding of the sediments).
Compaction
Occurs when rock particles or sediments are pressed together or packed down by gravity and the pressure of overlying rock layers.
Cementation
Occurs when compacted sediments stick together and turn into rock.