Introduction to Minerals

Definition of a Mineral

• A mineral is defined as a naturally occurring, inorganic solid.
• It possesses a crystal structure and has a definite chemical composition.

Characteristics of Minerals

• To qualify as a mineral, a substance must be:
  • Naturally occurring
  • Inorganic
  • Solid
  • Have a crystal structure
  • Possess a definite chemical composition

Streak

• Streak refers to the color of a mineral's powder when it is scratched or rubbed against a surface.

Luster

• Luster describes how light interacts with the surface of a mineral, indicating its shine or reflectiveness.

Color of a Mineral

• The color of a mineral offers limited information about its identity and is not a reliable diagnostic property.

Density Calculation

• Density is calculated using the formula:
  • Density = mass/volume
  • Example calculation: For a mass of 300 grams and a volume of 30 cm³, the density is 10 g/cm³.

MOHs Hardness Scale

• The MOHs hardness scale ranks ten minerals from the softest to the hardest, providing a relative measure of a mineral's hardness.

Fracture and Cleavage

• Cleavage is a property of minerals that split easily along flat surfaces.
• Fracture describes the appearance of a mineral when it breaks in an irregular manner.

Difference Between Fracture and Cleavage

• Cleavage allows for easy identification when a mineral splits along specific planes.
• Fracture indicates irregular breaks and can assist in identifying minerals that do not cleave.

Amber as a Mineral

• Amber is formed from hardened resin of alpine trees and is used in jewelry.
• It is classified as a mineral due to its natural occurrence and solid form, despite being organic in origin.