Unearthing Foundations: Rocks & Minerals
Rocks and minerals explore the different types of rocks—igneous, sedimentary, and metamorphic—and the minerals that form them, alongside the rock cycle, revealing Earth’s geological building blocks. Minerals are naturally occurring solids with specific compositions, like quartz, while rocks are aggregates of minerals, cycling through formation, transformation, and reformation, offering insights into Earth’s history and processes like mountain building or erosion.
Overview of Rocks & Minerals
Rocks and minerals are defined by their types, compositions, and the cyclical process that transforms them. Here’s the breakdown:
- Minerals: Naturally occurring, inorganic solids with a definite chemical composition and crystalline structure.
- Igneous Rocks: Rocks formed from cooled and solidified magma or lava.
- Sedimentary Rocks: Rocks formed from compacted and cemented sediments, often containing fossils.
- Metamorphic Rocks: Rocks transformed by heat and pressure without melting.
- Rock Cycle: The continuous process of rock formation, transformation, and reformation through geological processes.
Examples of Rocks & Minerals
Minerals Examples
- Quartz (SiOâ‚‚) forms clear crystals in many rocks.
- Feldspar, a common mineral, makes up much of Earth’s crust.
- Calcite (CaCO₃) fizzes with acid, often found in limestone.
Igneous Rocks Examples
- Granite forms from cooled magma, with visible quartz and feldspar grains.
- Basalt, a dark rock, forms from lava at mid-ocean ridges.
- Obsidian, a glassy volcanic rock, cools rapidly from lava.
Sedimentary Rocks Examples
- Limestone forms from compacted marine shells, rich in calcite.
- Sandstone results from cemented sand grains, often found in deserts.
- Shale forms from compacted mud, splitting into thin layers.
Metamorphic Rocks Examples
- Marble, transformed limestone, is used in sculptures.
- Slate, altered shale, forms from heat and pressure, used in roofing.
- Gneiss, develops from granite under intense pressure, showing banded layers.
Rock Cycle Examples
- Igneous basalt weathers into sediment, forming sedimentary sandstone over time.
- Sedimentary limestone under heat and pressure becomes metamorphic marble.
- Metamorphic gneiss melts into magma, cooling into igneous granite.