Chapter 2: Earth Process — Minerals, Rocks, Weathering, and Soil (Vocabulary)

A comprehensive set of vocabulary flashcards covering minerals, rocks, the rock cycle, weathering, erosion, and soil concepts from the lecture notes.

Mineral

A naturally occurring, inorganic solid with a definite chemical composition and a crystalline structure, formed by geological processes.

Naturally occurring

Existing in nature, not manufactured or synthetic.

Inorganic

Not derived from living organisms; lacking carbon-hydrogen backbone typical of organic matter.

Solid

A state of matter with a definite shape and volume, as opposed to a liquid or gas.

Crystalline structure

A regular, repeating arrangement of atoms in a mineral.

Quartz

A common silica mineral (SiO2) often cited as a classic mineral example.

Feldspar

A group of rock-forming silicate minerals rich in aluminium and silica.

Calcite

A carbonate mineral (CaCO3) common in rocks and shells.

Sulfur

A native element mineral; yellow, non-metallic, and common in sulfide/oxide associations.

Kaoline / Kaolinite

A clay mineral used in ceramics; one of the common clay minerals.

Smectite

A group of expandable clay minerals.

Magma

Molten rock stored beneath the Earth’s surface.

Lava

Molten rock that erupts onto the surface of the Earth.

Crystallization

The process by which a melt cools and solidifies into crystals.

Evaporation (mineral formation)

Process by which minerals form when water evaporates, leaving dissolved substances behind.

Crystal size

The size of crystals, influenced by the rate at which the melt or solution cools.

Color

Hue of a mineral; can vary due to impurities or trace elements.

Streak

Color of a mineral’s powder, often more diagnostic than surface color.

Luster

How a mineral reflects light; can be metallic, pearly, vitreous, or earthy.

Hardness

Resistance to scratching; measured on Mohs scale (1 to 10).

Mohs scale

A 1–10 scale used to rank mineral hardness from softest to hardest.

Cleavage

A mineral’s tendency to break along flat, defined planes.

Fracture

How a mineral breaks when it does not cleave, often irregular or conchoidal.

Specific gravity

A mineral’s density relative to that of water.

Habit

The typical appearance or shape of a mineral or its crystals.

Opaque

A material that does not transmit visible light.

Translucent

Permits light to pass through, but not detailed images.

Transparent

Light and clear images pass through a mineral.

Crystal form/structure

The external geometric shape or internal arrangement of atoms in a crystal.

Rock

A naturally occurring, coherent aggregate of one or more minerals.

Igneous

Rocks formed by cooling and solidification of molten material.

Sedimentary

Rocks formed by weathering, erosion, deposition, compaction, and cementation.

Metamorphic

Rocks formed by alteration of existing rocks under heat and pressure.

Weathering

Breakdown of rocks at or near the Earth’s surface into smaller pieces.

Physical (mechanical) weathering

Breaking rocks by physical forces (e.g., frost wedging, exfoliation, abrasion).

Chemical weathering

Rock breakdown driven by chemical reactions (e.g., dissolution, oxidation).

Exfoliation

Shedding of outer rock layers due to pressure release or temperature changes.

Frost wedging

Water freezes in cracks, expands, and fractures rocks.

Salt wedging

Salt crystal growth in pores/cracks that pries rocks apart.

Abrasion

Wearing away of rocks by friction and impact.

Burrowing of animals

Animals move rock fragments to the surface, exposing them to weathering.

Plant roots

Growing roots exert pressure that can break rocks apart.

Erosion

Removal and transport of weathered material by water, wind, ice, or gravity.

Deposition

Laying down of sediment in a new location.

Mass movement

Down-slope movement of rock and soil under gravity (e.g., landslides).

Sedimentation

Process of particles settling out of suspension and forming layers.

Detrital (clastic) rocks

Sedimentary rocks made from fragmented pre-existing rocks.

Organic detrital

Detrital rocks derived from the accumulation of plant/animal remains.

Inorganic detrital

Detrital rocks formed from mineral fragments produced by erosion.

Conglomerate

Detrital sedimentary rock consisting of rounded clasts cemented together.

Limestone

Sedimentary rock mainly composed of calcium carbonate (CaCO3).

Sandstone

Sedimentary rock made of sand-sized grains.

Gypsum

Sulfate mineral and evaporite; common in sedimentary rocks.

Shale

Fine-grained detrital sedimentary rock formed from mud.

Intrusive

Igneous rocks that crystallize below the surface; typically large crystals.

Extrusive

Igneous rocks that erupt onto the surface; typically fine-grained or glassy.

Phyllite

Low-grade metamorphic rock with foliated, glossy sheen.

Schist

Medium- to high-grade foliated metamorphic rock with pronounced mineral alignment.

Gneiss

High-grade foliated metamorphic rock with banded mineral layers.

Quartzite

Metamorphic rock formed from sandstone; very hard.

Marble

Metamorphic rock formed from limestone; reacts with acids.