Lithosphere l2

Definition: Lithosphere

The outer solid layer of the Earth made of rocks.

Hierarchy of Lithosphere

Lithosphere → Rocks → Minerals → Elements.

Definition: Mineral

Inorganic solid with a fixed chemical composition and regular crystalline structure.

Basic Building Block of Rocks

Minerals.

Mineral Interaction: Soil

Minerals interact with water and air to lead to soil formation.

Mineral Interaction: Nutrients

Minerals interact with the environment to release nutrients.

Mineral Interaction: Movement

Minerals allow for the movement of water and gases through Earth.

Property: Hardness

A physical property showing how resistant a mineral is to scratching.

Measurement: Hardness

Measured using the Mohs scale from 1 (softest) to 10 (hardest).

Hardness: Gypsum

Low hardness (about 2); soft; easy to crush; and scratches easily.

Hardness: Quartz

High hardness (about 7); hard; scratch-resistant; and used in glass.

Construction: Hard minerals

More resistant to weathering (Examples: Granite and Sandstone).

Construction: Soft minerals

Less resistant to weathering (Example: Limestone).

Hard Rock Usage

High-hardness rocks like granite are used in hospitals and train stations to resist erosion.

Statue Hardness: Khafre

Made of Diorite with a hardness of 7.

Statue Hardness: Ramses II

Made of Red granite with a hardness of 6 to 7.

Statue Hardness: The Sphinx

Made of Limestone with a hardness of 3 to 4.

Statue Hardness: Amenhotep III

Made of Alabaster with a hardness of 2.5 to 3.

Hardness Tool: Human Fingernail

Hardness of 2.5.

Hardness Tool: Copper Coin

Hardness of 3.

Hardness Tool: Steel Nail

Hardness of 4.5.

Property: Color

Helps identify minerals with distinctive colors like Malachite (green).

Problem with Color identification

One mineral can have many colors (Calcite) or different minerals can share the same color.

Definition: Luster

How light reflects from the surface of a mineral.

Example: Metallic Luster

Gold and Pyrite (shiny like metal).

Example: Glassy Luster

Quartz and Calcite (looks like glass).

Example: Matte Luster

Basalt (surface is not shiny).

Fact: Fool's Gold

Pyrite is called fool's gold because it looks like gold but has different density/composition.

Definition: Specific Gravity

The ratio between the mass of a substance and the mass of the same volume of water at 4°C.

Unit: Specific Gravity

It has no unit because it is a ratio.

Example: Heavy Mineral

Galena (Lead Sulphide) because it contains heavy elements.

Example: Light Mineral

Feldspar because it contains light elements.

Engineering use: Specific Gravity

Helps determine underground composition and what lies beneath without drilling.

Definition: Cleavage

Ability of a mineral to split along specific crystalline extensions; results in smooth and symmetrical surfaces.

Definition: Fracture

The pattern when a mineral breaks without following specific crystalline extensions; results in smooth and non-symmetrical surfaces.

Example: Mica Cleavage

Excellent cleavage in one direction; splits into thin sheets.

Example: Feldspar Cleavage

Cleavage in two or three directions at specific angles.

Example: Quartz Fracture

Has conchoidal fracture.

Risk: Cleavage in Building

Minerals with clear cleavage break easily under stress causing cracks or collapse.

Major Mineral Group: Silicates

Forms most of the Earth's crust; hard; and resistant to weak acids.

Major Mineral Group: Carbonates

Example is Calcite; soluble in weak acids; and produces CO2 gas bubbles.

Chemical Reaction: Carbonate + Acid

Produces effervescence (bubbles) and releases Calcium and Bicarbonate ions.

Test: Silicate vs Carbonate

Add dilute acid; Carbonates produce bubbles while Silicates do not react.

Mineral Formation: Magma

Minerals form when magma cools and solidifies (Crystallization).

Mineral Formation: Evaporation

Mineral salts precipitate when water evaporates.

Mineral Formation: Heat and Pressure

Atoms rearrange when rocks are subjected to high heat and pressure.

Stability: Cohesion

Minerals give rocks their hardness and cohesion.

Stability: Geography

Minerals help in the formation of continents and mountains.

Stability: Natural Processes

Minerals support the rock cycle and movement of tectonic plates.