Rocks and Minerals Study Guide

Vocabulary flashcards covering the properties of minerals, mineral identification tests, Moh's hardness scale, rock classification, and the rock cycle.

Mineral

A substance that meets five specific requirements: naturally occurring, inorganic, solid, definite composition, and crystalline structure.

Naturally Occurring

Formed by natural processes and not made by people.

Inorganic

Not produced by living organisms (for example, a desk is inorganic, whereas a log is organic).

Solid (Mineral Requirement)

Having a definite volume and shape at ordinary conditions.

Definite Composition

Having a specific chemical composition or limited range.

Crystalline Structure

An arrangement where atoms are arranged in an orderly, repeating pattern.

Color (Mineral Property)

The visible surface color of a mineral; it is a useful clue, but should never be used alone because one mineral can vary in color and different minerals can look alike.

Luster

How a mineral reflects light, classified either as metallic (looks like metal) or non-metallic (glassy, pearly, waxy, dull).

Cleavage

A breakage pattern observed on surfaces where a mineral breaks along flat planes of weakness.

Fracture

A breakage pattern where a mineral exhibits irregular breakage.

Streak

A test where a mineral is rubbed on a streak plate to produce powder.

Streak Color

The color of the powder observed after performing the streak test.

Hardness Scratch Rule

If a mineral scratches an object, it is at least as hard; if it cannot scratch an object, it is softer.

Hardness Test Sequence

A test to determine what a mineral can scratch by trying a penny, then glass, then a streak plate.

Moh's Scale

A relative hardness scale ranging from 1 to 10: 1 Talc, 2 Gypsum, 3 Calcite, 4 Flurite, 5 Apatite, 6 Feldspar, 7 Guartz, 8 Topaz, 9 Corundum, and 10 Diamond.

Magnet Test

A test to observe whether a mineral is attracted to a magnet.

Rock

A naturally occurring solid aggregate of one or more minerals or mineral or mineral-like-materials.

Main Classification Rule for Rocks

Rocks are classified primarily by how they formed.

Gem

A precious or semiprecious stone, especially when cut and polished, or engraved.

Ore

A rock that contains a metal that can be sold for a profit (for example, aluminum and copper).

Igneous Rock

Rock formed when magma or lava cools and solidifies; possible clues include visible crystals, glassy texture, or gas holes.

Sedimentary Rock

Rock formed when materials are deposited, then compacted and cemented; possible clues include grains, layers, rounded peices, or fossils.

Metamorphic Rock

Rock formed when an existing rock changes from heat and pressure without melting; possible clues include foliation, banding, and flattened texture.

Heat + Pressure (Rock Cycle Process)

An internal process where existing rock changes while remaining solid into metamorphic rock.

Melting (Rock Cycle Process)

An internal process where rock becomes molten material to form magma (or lava at the surface).

Cooling + Crystallization

An internal process where magma or lava cools and solidifies into igneous rock.

Weathering + Erosion

Processes that break down any existing rock and transport the fragments into sediments.

Deposition, Compaction + Cementation

The processes that deposit loose sediments and compact and cement them into sedimentary rock.