Rocks and Minerals Atoms, Elements, Isotopes, Ions, and Compounds Minerals–General Types of Minerals Rocks

Minerals- the building blocks Atomic Structure Elements and Isotopes Ions Compounds

Rocks and Minerals Minerals Defined Identifying Characteristics of Minerals Other Physical Properties of Minerals

Halite Crystal Source: Photograph © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

Galena Source: Photograph © The McGraw-Hill Companies, Inc./Doug Sherman, photographer.

Fluorite Source: Photograph © The McGraw-Hill Companies, Inc./Doug Sherman, photographer.

Halite Source: Photograph © The McGraw-Hill Companies, Inc./Doug Sherman, photographer.

Definition of a Mineral “A naturally occurring, inorganic, solid element or compound with a definite chemical composition and a regular internal crystal structure.”

Mineral Characteristics Chemical composition –Diamond = graphite (both are pure carbon) Crystal structure –Diamond ≠ graphite

Cubic Structure of Halite Source: Photograph © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

Mineral Properties Hardness (Mohs hardness scale) –See appendix C Cleavage (how it breaks- atomic scale) Luster- the surface ‘sheen’ Color is not a good property for i.d. –Corundum (Al 2 O 3 )

Minerals: two groups Silicates (Si + O ± other elements) –All built with ‘silicon tetrahedra’ –4 O atoms, 1 Si atom, 4 - charge –Quartz, feldspars –Olivine (peridot) ferromagnesian (Fe, Mg) –Asbestos –Micas –Clays (tropical weathering)

Minerals: non-silicates NonsilicatesExample –Carbonates (CO 3 ): calcite –Sulfates (SO 4 ): gypsum –Sulfides (metal + S): pyrite –Oxides (metal + O): hematite –Hydroxides (metal + OH): gibbsite –Halides (metal + halide): salt (halite) –Native elements Au, Ag, Pt, Cu, C

Rocks The Rock Cycle Igneous Rocks Sediments and Sedimentary Rocks Metamorphic Rocks The Rock Cycle Revisited

Definition of a Rock A solid, cohesive aggregate of one or more minerals or mineral materials Important for construction Geologic history

The Rock Cycle Earth as a constantly changing system Plate tectonics 3 types of rocks on Earth –Igneous –Sedimentary –Metamorphic

The Rock Cycle Igneous Rocks –Formed by the crystallization of magma –Usually made up of silicate minerals –Plutonic: solidified inside Earth (granite) –Volcanic: solidified on Earths surface (lava)

Granite, a Plutonic Rock Source: Courtesy of Carla W. Montgomery.

Obsidian, Volcanic Glass Source: Photograph © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

Basalt, a Volcanic Rock Source:Courtesy of Carla W. Montgomery.

Porphyry, an Igneous Rock Source: Photograph © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

The Rock Cycle Sedimentary Rocks –Chemical precipitation Limestone (carbonate), chert –Clastic sedimentation Sandstone, shale, conglomerate

Limestone Source: Photograph by I.J. Witkind, USGS Photo Library, Denver, CO.

Shale Source: Photograph © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

Sandstone Source: Photograph © The McGraw-Hill Companies, Inc./Doug Sherman, photographer.

Conglomerate Source: Courtesy of Carla W. Montgomery.

The Rock Cycle Metamorphic Rocks –Changed form –Heat, pressure, fluids –Metamorphism: contact vs. regional

Marble Source: Courtesy of Carla W. Montgomery.

Quartzite Source: © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

Schist Source: Courtesy of Carla W. Montgomery.

Gneiss Figure 2.12D 2-19 Source: Courtesy of Carla W. Montgomery.