© 2012 Pearson Education, Inc. Earth Science, 13e Tarbuck & Lutgens

© 2012 Pearson Education, Inc. Matter and Minerals Earth Science, 13e Chapter 2 Stanley C. Hatfield Southwestern Illinois College

© 2012 Pearson Education, Inc. Minerals: the building blocks of rocks  Definition of a mineral Natural Inorganic Solid Possess an orderly internal structure of atoms Have a definite chemical composition  Rock – any naturally occurring solid mass of mineral or mineral-like matter

© 2012 Pearson Education, Inc. Composition and structure of minerals  Elements Basic building blocks of minerals Over 100 are known  Atoms Smallest particles of matter Have all the characteristics of an element

© 2012 Pearson Education, Inc. Periodic table of the elements

© 2012 Pearson Education, Inc. How atoms are constructed  Nucleus – central part of an atom that contains Protons – positive electrical charges Neutrons – neutral electrical charges  Energy levels, or shells Surround nucleus Contain electrons – negative electrical charges

© 2012 Pearson Education, Inc. Simplified view of the atom

© 2012 Pearson Education, Inc. How atoms are constructed  Atomic number is the number of protons in an atom’s nucleus  Bonding of atoms Forms a compound with two or more elements Ions are atoms that gain or lose electrons  Isotopes Have varying number of neutrons

© 2012 Pearson Education, Inc. How atoms are constructed  Isotopes Have different mass numbers – the sum of the neutrons plus protons Many isotopes are radioactive and emit energy and particles

© 2012 Pearson Education, Inc. Minerals  Physical properties of minerals Habit – common crystal shape Luster – appearance in reflected light Color Streak – color of mineral in powdered form Hardness – ability to resist scratching or abrasion Cleavage – tendency to break along planes of weak bonding

© 2012 Pearson Education, Inc. Good crystals of the mineral pyrite

© 2012 Pearson Education, Inc. Galena displays metallic luster

© 2012 Pearson Education, Inc. Mohs scale of hardness

© 2012 Pearson Education, Inc. Minerals  Physical properties of minerals Fracture – random pattern of breakage Specific gravity – mineral density Other properties Taste Smell Elasticity Malleability

© 2012 Pearson Education, Inc. Conchoidal fracture

© 2012 Pearson Education, Inc. Minerals  Physical properties of minerals Other properties Feel Magnetism Double Refraction Reaction to hydrochloric acid

© 2012 Pearson Education, Inc. Minerals  A few dozen minerals are called the rock-forming minerals The eight elements that compose most rock-forming minerals are oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg) Most abundant atoms in Earth’s crust are oxygen (46.6% by weight) and silicon (27.7% by weight)

© 2012 Pearson Education, Inc. Composition of continental crust

© 2012 Pearson Education, Inc. Minerals  Mineral groups Rock-forming silicates Most common mineral group Contain the silicon-oxygen tetrahedron (molecule) Four oxygen atoms surrounding a much smaller silicon atom Combines with other atoms to form the various silicate structures

© 2012 Pearson Education, Inc. The silicate (SiO 4 ) -4 molecule

© 2012 Pearson Education, Inc. Minerals  Mineral groups Rock-forming silicates Groups based upon tetrahedral arrangement Olivine – independent tetrahedra Pyroxene group – tetrahedra are arranged in chains Amphibole group – tetrahedra are arranged in double chains

© 2012 Pearson Education, Inc. Hornblende – a member of the amphibole group

© 2012 Pearson Education, Inc. Minerals  Mineral groups Rock-forming silicates Groups based upon tetrahedral arrangement Micas – tetrahedra are arranged in sheets Two types of mica are biotite (dark) and muscovite (light) Feldspars – Three-dimensional network of tetrahedra

© 2012 Pearson Education, Inc. Minerals  Mineral groups Rock-forming silicates Groups based upon tetrahedral arrangement Feldspars – most abundant group of minerals in Earth’s crust Quartz – three-dimensional network of tetrahedra

© 2012 Pearson Education, Inc. Potassium feldspar

© 2012 Pearson Education, Inc. Minerals  Mineral groups Nonsilicate minerals Major groups Oxides Sulfides Carbonates Halides Native elements

© 2012 Pearson Education, Inc. Common nonsilicate mineral groups

© 2012 Pearson Education, Inc. Minerals  Mineral groups Nonsilicate minerals Carbonates A major rock-forming group Found in the rocks limestone and marble Halite and gypsum are found in sedimentary rocks Many have economic value

© 2012 Pearson Education, Inc. Minerals  Mineral resources Mineral resources are occurrences of useful minerals that will eventually be extracted Ore deposits are concentrations of metallic minerals that can be mined at a profit Economic factors may change and influence a resource

© 2012 Pearson Education, Inc. An underground halite (salt) mine

© 2012 Pearson Education, Inc. End of Chapter 2