Rocks and Minerals

Igneous Rocks

• Formed by cooling and solidification of molten rock (magma or lava).
• Intrusive (Plutonic): Develops beneath the Earth's surface; examples include granite.
• Extrusive (Volcanic): Occurs on the Earth's surface; examples include basalt.

Sedimentary Rocks

• Created from the accumulation and lithification of sediment.
• Clastic: Composed of fragments from other rocks; examples include sandstone.
• Chemical: Forms from mineral precipitation out of water; a common example is limestone.
• Organic: Includes organic material; a key example is coal.

Metamorphic Rocks

• Result from the transformation of existing rocks through heat, pressure, and chemical processes.
• Example: Marble forms from the metamorphosis of limestone.

Minerals

• Defined by being naturally occurring, inorganic, solid substances with a definite chemical composition and ordered internal structure.
• Properties include:
  • Hardness: Measured using the Mohs scale, which ranks minerals from 1 (talc) to 10 (diamond).
  • Luster: The way light interacts with the surface of a mineral.
  • Color: The apparent hue of the mineral.
  • Streak: The color of the mineral in powdered form.
  • Cleavage: The tendency of a mineral to break along flat planes.
  • Fracture: The way a mineral breaks other than along cleavage planes.
  • Specific Gravity: The ratio of a mineral's weight to the weight of an equal volume of water.

This quiz explores the various types of rocks, focusing on igneous and sedimentary categories. Understand the differences between intrusive and extrusive igneous rocks as well as the various forms of sedimentary rocks. Test your knowledge on the origin and composition of these essential geological materials.