Elements Minerals and Rocks 1 Various elements combine to form minerals 2 Minerals combine to form rocks 3 Rocks are made up of one or many minerals Minerals 1 What is a mineral 2 The term mineral is used in two different ways in our society a Refers to an element such as K or Ca in a vitamin supplement This is not how we are defining it 3 How do we define minerals Definition of Minerals for Geology 1 It is a naturally occurring substance a Synthetic gemstones are not minerals 2 3 It is a solid substance not a liquid or a gas Ice is considered a mineral It is an inorganic compound This means it does not contain Carbon In chemistry we say that a substance is organic meaning it contains carbon This has nothing to do with how the term organic is commonly used 4 Minerals have a crystalline structure 5 There is a definite chemical composition 6 The most common mineral is quarts 7 Feldspars are made up of Silicon and Oxygen they are divided into Orthoclase and 8 Common minerals make up the vast majority of rocks Plagioclase Mineral Classification 1 Most common group is Silicates includes quartz feldspars amphibole and pyroxene 2 There are 7 mineral classifications a Silicates 90 95 of all minerals and they are nonmetallic b Oxides Iron oxide hematite is an example i Oxygen bonded to a metal Iron is bonded to oxygen to create hematides c Sulfates Gypsum is used for sheetrock d Sulfides Pyrite fool s gold or Galena i Ore minerals e Carbonates minerals combined with Calcite i Carbon and oxygen bonded together in triangular arrangements f Native elements gold copper etc not combined with other minerals g Halides salts h Phosphate minerals there are many but the most common is apatite i Common in the production of fertilizers ii Larges phosphate mine is in Aurora NC Isotopes are atoms with an extra number or neutrons The atomic weight is an average 3 4 016 and 018 are both isotopes of Oxygen There is vastly more than 016 and 018 a There can only be two protons in every element s orbital Chemical Bonding 1 Atoms bond to one another under temperature and pressures that occur in the earth 2 Some form Ionic compounds a One proton is given away b The strongest type of bond 3 Some form Covalent compounds a Share an electron 4 Some for Metallic compounds a Sea of electrons b This is why metal is malleable and they are not rigidly bonded 5 Nature can make many variations using the Tetrahedron a Amphibole has a double chained tetrahedron 6 Cubic shaped axis a Mineral can be made into a cube b Mineral can be made into an octahedron c Mineral can be made into a dodecahedron 7 Longer shaped axis a Mineral can be made into a rhombus 8 There are 7 different crystal categories 9 Can have cubic hexagonal tetragonal orthorhombic monoclinic 10 Cubic minerals have three different directions of cleavage a Cleavage mineral breakage