GEOL 103

Mineral

Naturally occurring, homogeneous, inorganic solid substance with a definite chemical composition and characteristic crystalline structure.

Rock

An aggregate of minerals or materials constituting the Earth's crust, which can be unconsolidated (like sand) or consolidated (like granite).

Igneous Rocks

Rocks formed from the solidification of molten material, classified as intrusive or extrusive based on their formation environment.

Sedimentary Rocks

Rocks formed through the processes of weathering, transportation, deposition, and diagenesis, often containing visible grains.

Metamorphic Rocks

Rocks formed from the alteration of existing rocks (igneous, sedimentary, or metamorphic) due to heat, pressure, and hydrothermal fluids.

Luster

The way light is reflected from the surface of a mineral; can be metallic or nonmetallic.

Streak

The color of a mineral in powdered form, observed by rubbing the mineral on a streak plate.

Hardness

A measure of how resistant a mineral is to being scratched, typically determined using the Mohs scale.

Cleavage

The tendency of a mineral to break along specific planes where bonds are weaker, producing smooth surfaces.

Fracture

Breakage of a mineral along irregular surfaces, not along cleavage planes.

Felsic

Light-colored igneous rocks composed primarily of silica and feldspar, typically containing quartz.

Mafic

Dark-colored igneous rocks rich in iron and magnesium, typically composed of minerals like amphibole and pyroxene.

Clastic Rocks

Sedimentary rocks formed from fragments of other rocks and minerals, classified by grain size.

Biochemical Rocks

Sedimentary rocks formed from the accumulation of organic materials, such as shells or plant debris.

Foliated Metamorphic Rocks

Metamorphic rocks with a layered or banded appearance due to the alignment of platy minerals under pressure.

Non-Foliated Metamorphic Rocks

Metamorphic rocks that do not exhibit layering or banding, formed under conditions without directional stress.

Normal Fault

A fault in which the hanging wall moves down relative to the foot wall, typically associated with extensional forces.

Reverse Fault

A fault where the hanging wall moves up relative to the foot wall, associated with compressional forces.

Syncline

A fold in rock layers that forms a U-shape, with the youngest rocks in the center.

Anticline

A fold in rock layers that forms an arch-shape, with the oldest rocks in the center.