Rocks and Minerals Lesson

Introduction

Rocks and minerals are naturally occurring substances that make up the Earth's crust. While rocks are solid aggregates of minerals, minerals are naturally occurring crystalline substances.

Types of Rocks

There are three main types of rocks: igneous, sedimentary, and metamorphic.

• Igneous Rocks: Formed from cooling and solidification of molten rock (lava or magma). Example: Granite, Basalt.
• Sedimentary Rocks: Formed by the accumulation of sediments over time, often in water. Example: Limestone, Sandstone.
• Metamorphic Rocks: Formed when existing rocks are altered by high pressure and temperature. Example: Marble, Schist.

Types of Minerals

Minerals are solid, inorganic substances with a specific chemical composition. Some common minerals include quartz, feldspar, and calcite.

Characteristics of Minerals:

• Hardness: Measured on the Mohs scale (from 1 for talc to 10 for diamond).
• Color: The appearance of the mineral.
• Luster: How the mineral reflects light (metallic, glassy, pearly, etc.).
• Cleavage: How the mineral breaks (into flat sheets or irregular pieces).

Interactive Tutorial: Rock Types Diagram

Click on different rocks in the diagram to learn more about them.

Quiz: Test Your Knowledge