Minerals & Rocks – Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering the key terms, groups, processes, textures, and tests associated with minerals and rocks as presented in the lecture notes.

Mineral

A naturally occurring, inorganic solid with a definite chemical composition and orderly crystal structure.

Inorganic

Not derived from living organisms; lacking organic carbon.

Solid (mineral context)

State of matter with definite shape and volume; minerals must be solid at room temperature.

Chemical Composition

The fixed ratio and kinds of elements that make up a mineral.

Crystal Structure

The repeating, orderly arrangement of atoms inside a mineral.

Silicate Mineral

Mineral built from silicon–oxygen tetrahedra (SiO4); forms about 90 % of Earth’s crust.

Non-silicate Mineral

Mineral that lacks SiO2; includes carbonates, oxides, sulfides, etc.; roughly 8 % of the crust.

Native Element

Mineral made of a single element in pure form, e.g., gold or sulfur.

Sulfide

Non-silicate mineral containing sulfur anions bonded to metals, e.g., pyrite (FeS₂).

Sulfate

Mineral containing the sulfate ion (SO₄²⁻), e.g., gypsum.

Oxide

Mineral where oxygen bonds to one or more metals, e.g., hematite (Fe₂O₃).

Hydroxide

Oxide subgroup that contains the hydroxyl ion (OH)⁻, e.g., portlandite.

Halide

Mineral containing halogen ions (Cl⁻, F⁻, Br⁻, I⁻), such as halite (NaCl).

Carbonate

Mineral containing the carbonate ion (CO₃²⁻); calcite is an example.

Cubic Crystal System

Crystals with three equal axes at 90° (e.g., galena, halite).

Tetragonal Crystal System

Two equal horizontal axes, one different vertical axis at 90° (e.g., chalcopyrite).

Hexagonal Crystal System

Three equal 120° axes and one vertical axis (e.g., quartz).

Orthorhombic Crystal System

Three unequal axes all at 90° (e.g., olivine).

Monoclinic Crystal System

Three unequal axes; two at 90°, one oblique (e.g., mica).

Triclinic Crystal System

Three unequal, all oblique axes (e.g., feldspar).

Crystallization from Magma

Process where cooling magma or lava solidifies and minerals grow.

Evaporation Precipitation

Minerals form when water evaporates, leaving dissolved ions to crystallize.

Supersaturation Precipitation

Minerals drop out of solution when water becomes saturated or conditions change.

Color (mineral)

Surface hue of a mineral; unreliable due to impurities and weathering.

Streak

Color of a mineral in powdered form left on a porcelain plate.

Luster

Manner in which a mineral reflects light; metallic or non-metallic.

Metallic Luster

Bright, mirror-like reflectance similar to polished metal.

Non-metallic Luster

Subtler shine—glassy, pearly, dull, waxy, brilliant, etc.

Hardness

Resistance to scratching; measured by Mohs scale.

Mohs Hardness Scale

Relative scale (1–10) ranking minerals from talc (1) to diamond (10).

Cleavage

Tendency of a mineral to split along flat planes of weakness.

Fracture

Irregular breakage of a mineral not along cleavage planes.

Density (Heft)

Mass per volume; how heavy a mineral feels for its size.

Effervescence

Reaction of a mineral (e.g., calcite) with acid that releases CO₂ bubbles.

Oxidation (mineral test)

Chemical reaction of minerals with oxygen, forming rust or patina.

Magnetism

Attraction to magnets shown by minerals like magnetite (lodestone).

Double Refraction

Optical effect where a mineral (e.g., Iceland spar) splits light into two images.

Radioactivity

Emission of radiation from minerals with unstable nuclei (e.g., pitchblende).

Ore

Mineral or rock that can be mined profitably for its useful elements.

Metal

Shiny, conductive, malleable element extracted from certain ores.

Nonmetal

Dull, brittle element that is a poor conductor; mined for various uses.

Alloy

Mixture of two or more metals (or metal with nonmetal), such as bronze.

Gem

Mineral valued for beauty, rarity, and durability; cut for jewelry.

Monomineralic Rock

Rock composed of a single mineral, e.g., marble (calcite).

Polymineralic Rock

Rock containing two or more minerals, e.g., granite.

Igneous Rock

Rock formed by cooling and solidifying magma or lava.

Sedimentary Rock

Rock formed from lithified sediments, precipitates, or organic remains.

Metamorphic Rock

Rock altered by heat, pressure, and/or chemically active fluids.

Clastic Sedimentary Rock

Rock of compacted and cemented fragments of pre-existing rocks.

Chemical Sedimentary Rock

Rock precipitated from mineral-rich water as it evaporates or cools.

Organic Sedimentary Rock

Rock formed from accumulated plant or animal debris (e.g., coal).

Conglomerate

Clastic sedimentary rock with rounded gravel-size clasts.

Breccia

Clastic sedimentary rock with angular gravel-size fragments.

Sorting

Uniformity of grain sizes in a sediment or sedimentary rock.

Fossil

Preserved remains or traces of once-living organisms in rock.

Strata

Horizontal layers or beds of sedimentary rock.

Extrusive Igneous Rock

Igneous rock that cools quickly at or near the surface; fine-grained.

Intrusive Igneous Rock

Igneous rock that cools slowly underground; coarse-grained.

Magma

Molten rock beneath Earth’s surface.

Lava

Molten rock erupted onto Earth’s surface.

Glassy Texture

Igneous texture with no crystals due to very rapid cooling (e.g., obsidian).

Vesicular Texture

Igneous texture containing gas bubble holes (e.g., pumice, scoria).

Fine-grained Texture

Igneous rock with crystals under 1 mm from rapid cooling.

Coarse-grained Texture

Igneous rock with crystals 1 mm or larger from slow cooling.

Mafic Composition

Igneous rocks rich in iron and magnesium; dark and dense.

Felsic Composition

Igneous rocks rich in silicon and aluminum; light-colored and less dense.

Metamorphism

Process that changes rock by heat, pressure, and fluids without complete melting.

Contact Metamorphism

Metamorphism caused by heat from nearby magma or lava.

Regional Metamorphism

Large-scale metamorphism due to tectonic pressure and heat during mountain building.

Foliated Texture

Metamorphic texture with minerals aligned in parallel layers or bands.

Banding

Alternating dark and light mineral layers in foliated rocks like gneiss.

Mineral Alignment

Parallel orientation of platy or needle minerals caused by pressure.

Non-foliated Texture

Metamorphic texture lacking layered structure; crystals randomly oriented.

Recrystallization

Growth of new mineral grains during metamorphism without melting.

Partial Melt

State where only some minerals in a rock melt under high temperature.

Rock Cycle

Continuous processes that transform rocks between igneous, sedimentary, and metamorphic forms.

Sediment

Loose particles of rock, mineral, or organic material transported by wind, water, or ice.

Compaction

Process where overlying weight squeezes sediments, reducing pore space.

Cementation

Process where dissolved minerals precipitate and bind sediment grains.

Precipitate (geology)

Solid mineral that forms and settles out of solution.

Heat (metamorphic agent)

Thermal energy that drives recrystallization and new mineral growth.

Pressure (metamorphic agent)

Force that aligns minerals and increases density during metamorphism.

Chemical Activity

Action of hot fluids that add or remove ions, accelerating metamorphic reactions.

Heft

Informal test of relative mineral density by hand weight.