Earth Characteristics and Subsystems

Atmosphere:
- Contains oxygen and nitrogen, essential for respiration and protection from harmful solar radiation.
Water:
- Presence of liquid water, covering 71% of Earth's surface, is crucial for all known life forms.
Temperature:
- The range of temperatures on Earth supports diverse ecosystems, with a stable climate due to the greenhouse effect.
Nutrients:
- Availability of essential nutrients (carbon, nitrogen, phosphorus) supports biological processes.
Magnetic Field:
- Protects the planet from solar wind and cosmic radiation, creating a stable environment for life.

Geosphere:
- The solid Earth, including rocks, minerals, and landforms.
Hydrosphere:
- All water on Earth, including oceans, rivers, lakes, and groundwater.
Atmosphere:
- The layer of gases surrounding the Earth, influencing weather and climate.
Biosphere:
- All living organisms and their interactions with the other subsystems.
Cryosphere:
- All frozen water on Earth, including glaciers and polar ice caps.

Physical Properties:
- Color: External appearance, can vary widely.
- Streak: Color of the mineral in powdered form.
- Luster: Appearance of light reflected from the mineral's surface (metallic, glassy, dull).
- Hardness: Resistance to scratching, measured by the Mohs scale.
- Cleavage: Tendency to break along flat surfaces.
- Fracture: Irregular breakage patterns.
- Density: Mass per volume; can indicate mineral composition.
Chemical Properties:
- Composition: The specific elements and compounds that make up the mineral.
- Reactivity: How the mineral interacts with acids or other chemicals.
- Solubility: Ability to dissolve in water or other solvents.
- Crystal Structure: The orderly arrangement of atoms within the mineral.

Igneous Rocks:
- Formation: Formed from the cooling and solidification of molten rock (magma or lava).
- Types:
  - Intrusive (plutonic) – formed inside the Earth (e.g., granite).
  - Extrusive (volcanic) – formed on the surface (e.g., basalt).
Sedimentary Rocks:
- Formation: Formed by the accumulation and compaction of mineral and organic particles.
- Types:
  - Clastic – made from fragments of other rocks (e.g., sandstone).
  - Chemical – formed from dissolved minerals precipitating (e.g., limestone).
  - Organic – formed from the remains of living organisms (e.g., coal).
Metamorphic Rocks:
- Formation: Formed from existing rocks transformed by heat, pressure, or chemically active fluids.
- Types:
  - Foliated – exhibit layered or banded appearance (e.g., schist).
  - Non-foliated – do not have a layered appearance (e.g., marble).

Atmosphere of Earth is rich in oxygen and nitrogen, vital for respiration and blocking harmful solar radiation.
Liquid water covers 71% of the Earth's surface, essential for the survival of all known life forms.
Temperatures on Earth foster diverse ecosystems, maintained by a stable climate through the greenhouse effect.
Essential nutrients like carbon, nitrogen, and phosphorus are readily available, supporting biological processes.
Earth's magnetic field shields the planet from solar wind and cosmic radiation, contributing to a stable living environment.

Geosphere refers to the solid part of Earth, including rocks, minerals, and various landforms.
Hydrosphere encompasses all water on Earth, such as oceans, rivers, lakes, and groundwater sources.
Atmosphere is the gaseous layer surrounding Earth that shapes weather and climate patterns.
Biosphere includes all living organisms and their interactions with other subsystems of the planet.
Cryosphere is the frozen water component of Earth, comprising glaciers and polar ice caps.

Color reflects the external appearance of a mineral, which can vary significantly.
Streak is the color of a mineral when powdered, providing more consistent identification.
Luster describes how light interacts with a mineral's surface, classified as metallic, glassy, or dull.
Hardness gauges a mineral's resistance to scratching, measured using the Mohs scale.
Cleavage indicates the tendency of a mineral to break along flat, smooth surfaces.
Fracture describes how minerals break in irregular patterns when cleaved does not occur.
Density, defined as mass per volume, helps to determine a mineral's composition.
Composition pertains to the elements and compounds that constitute the mineral.
Reactivity assesses how minerals behave in the presence of acids or other reactive substances.
Solubility measures a mineral's ability to dissolve in water or other solvents.
Crystal Structure refers to the orderly arrangement of atoms, defining the mineral's characteristics.

Igneous Rocks form from the cooling and solidification of molten rock, either magma or lava.
- Intrusive (plutonic) rocks cool slowly within Earth, such as granite.
- Extrusive (volcanic) rocks solidify quickly on the surface, like basalt.
Sedimentary Rocks are produced from the accumulation and compaction of mineral and organic particles.
- Clastic sedimentary rocks are composed of fragments of other rocks, such as sandstone.
- Chemical sedimentary rocks form from precipitated dissolved minerals, exemplified by limestone.
- Organic sedimentary rocks consist of the remains of living organisms, like coal.
Metamorphic Rocks originate from pre-existing rocks altered by heat, pressure, or chemically active fluids.
- Foliated metamorphic rocks feature a layered appearance, such as schist.
- Non-foliated metamorphic rocks lack a layered structure, exemplified by marble.