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Earth Science, 10e. Edward J. Tarbuck & Frederick K. Lutgens . Minerals: Building Blocks of Rocks Chapter 1. Earth Science, 10e Stan Hatfield and Ken Pinzke Southwestern Illinois College. Minerals: the building blocks of rocks . Definition of a mineral Natural Inorganic Solid
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Earth Science, 10e Edward J. Tarbuck & Frederick K. Lutgens
Minerals: Building Blocks of RocksChapter 1 Earth Science, 10e Stan Hatfield and Ken Pinzke Southwestern Illinois College
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 • Mineraloid - lacks an orderly internal structure
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
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
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
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
Minerals • Physical properties of minerals • Crystal form • Luster • Color • Streak • Hardness • Cleavage
Three examples of perfect cleavage – fluorite, halite, and calcite
Minerals • Physical properties of minerals • Fracture • Specific gravity • Other properties • Taste • Smell • Elasticity • Malleability
Minerals • Physical properties of minerals • Other properties • Feel • Magnetism • Double Refraction • Reaction to hydrochloric acid
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)
Minerals • Mineral groups • Rock-forming silicates • Most common mineral group • Contain the silicon-oxygen tetrahedron • Four oxygen atoms surrounding a much smaller silicon atom • Combines with other atoms to form the various silicate structures
Minerals • Mineral groups • Rock-formingsilicates • Groups based upon tetrahedral arrangement • Olivine – independent tetrahedra • Pyroxene group – tetrahedra are arranged in chains • Amphibole group – tetrahedra are arranged in double chains
Minerals • Mineral groups • Rock-formingsilicates • 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
Minerals • Mineral groups • Rock-formingsilicates • Groups based upon tetrahedral arrangement • Feldspars • Two types of feldspar are Orthoclase and Plagioclase • Quartz – three-dimensional network of tetrahedra
Minerals • Mineral groups • Rock-formingsilicates • Feldspars are the most plentiful mineral group • Crystallize from molten material • Nonsilicate minerals • Major groups • Oxides • Sulfides
Minerals • Mineral groups • Nonsilicate minerals • Major groups • Sulfates • Carbonates • “Native” elements
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
Minerals • Mineral resources • Reserves are already identified deposits • Ores are useful metallic minerals that can be mined at a profit • Economic factors may change and influence a resource