Rocks, Minerals, and Fossils Study Guide

A set of flashcards to help review key terms and definitions related to rocks, minerals, and fossils, aiding in preparation for the lab exam.

Talc

Mohs hardness: 1; Color: white, grey, colorless, green; Streak: white to pale green; Luster: pearly.

Gypsum

Mohs hardness: 2; Color: clear, colorless, white, grey, yellow, red, brown; Streak: white; Luster: vitreous.

Calcite

Mohs hardness: 3; Color: white, colorless, grey, red, green, blue, yellow; Streak: white; Luster: vitreous; Special properties: reacts to acid.

Fluorite

Mohs hardness: 4; Color: purple, green, yellow, colorless; Streak: white; Luster: vitreous.

Apatite

Mohs hardness: 5; Color: brown, colorless, green, and many other colors; Streak: white; Luster: vitreous.

Potassium Feldspar

Mohs hardness: 6; Color: pink/reddish; Streak: white; Luster: vitreous.

Quartz

Mohs hardness: 7; Color: white, translucent, brown, black, pink, purple, etc.; Streak: colorless; Luster: vitreous.

Topaz

Mohs hardness: 8; Color: colorless, brown, grey, yellow, orange, red; Streak: colorless; Luster: vitreous.

Corundum

Mohs hardness: 9; Color: grey to brown; Streak: colorless; Luster: adamantine to vitreous.

Hematite

Mohs hardness: 5; Color: red to reddish, black to steel-grey; Streak: red to reddish brown; Luster: metallic and sometimes earthy.

Gabbro

An igneous rock characterized by a black matrix and interlocking crystals.

Rhyolite

An igneous rock with a very light grey matrix and no interlocking crystals.

Obsidian

An igneous rock with a black matrix and no interlocking crystals; displays specific sub-textures.

Pumice

A lightweight igneous rock that is white in color and floats in water.

Conglomerate

A sedimentary rock made of clasts greater than 2 mm in diameter with at least 50% rounded clasts.

Coal - Lignite

A sedimentary rock made of biological material, known as 'brown coal', with 70% carbon content.

Shale

A sedimentary rock with clasts less than 0.002 mm in diameter.

Marble

A non-foliated metamorphic rock; parent rock is always limestone or dolostone.

Quartzite

A non-foliated metamorphic rock; parent rock is always quartz sandstone.

Phylum: Arthropoda

Includes segmented body organisms such as trilobites, crabs, spiders, lobsters.

Phylum: Brachiopoda

Includes 'lamp shells' called brachiopods that exhibit bilateral symmetry.

Phylum: Mollusca

Includes animals like bivalves, cephalopods, and gastropods.

Permineralization

A fossil preservation process that turns the fossil to stone, commonly preserving teeth and bones.

Fossil Preservation: Carbonization

A process that retains the carbon outline of an organism, often seen in leaves.