CEE 1030 1st Edition Lecture 1 Minerals Building Blocks of Rocks What are minerals Definition of a mineral to a geologist ordered internal structure crystalline atoms arranged in ordered repeating array chemical composition that may vary within a defined range naturally occurring inorganic solid diamond mineral glass not a mineral not the same as mineral supplements dietary minerals are chemical elements needed by organisms What are Rocks loosely defined as any solid mass of mineral or mineral like matter that occurs naturally Most rocks are solid aggregates of minerals some rocks are composed of a single mineral e g marble typically the mineral calcite concrete not a rock most rocks made up of minerals some cases that rocks are made of non mineral matter ex non crystalline glassy volcanic rocks such as obsidian ex coal compacted plant remains composition of minerals every sample of the same mineral has the same elements joined in a consistent repeating pattern elements basic building blocks of minerals most minerals are a combination of 2 or more elements atoms smallest unit of an element nucleus contains most of the mass of the atom protons with a positive charge neutrons with no charge neutral electrons negative charge atomic number number of protons mass number number of protons and neutrons These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute electronic structure of atoms determines how atoms of elements bond together and with other elements electrons found in distinct energy shells iconic bonding atoms gain or lose outermost valence electrons to form ions how minerals have sodium and chloride ionic solid electrostatic attraction between positive cations and negative anions Covalent bonds atoms sharing electrons Most minerals on earth s surface have oxygen in them Polymorphs minerals with the same composition but different crystalline structures all same material different structure Examples of minerals quartz olivine fluorite beryl native copper diamond 1 physical properties crystal form external expression of a minerals internal structure crystal growth often interrupted due to competition for space and rapid loss of heat cubic crystals of Pyrite fools gold 2 physical properties luster way in which mineral surface reflects light shiny metallic Asbestos is a commercial term for minerals that form little fibers commercial term for variety of silicate minerals that readily separate into thin strong fibers Flexible heat resistant inert insulation car brake lining floor tiles 3 physical properties color obvious feature but often unreliable as a diagnostic property of a particular mineral gemstone names originate before mineral structure and composition were known ex mineral corundum tiny amounts of chromium red color ruby trace titanium and iron blue color sapphire 4 physical properties streak color of mineral in its powdered form obtained on an unglazed porcelain plate Hermatite found in many colors black steel silver grey brown red 5 Physical properties hardness resistance to abrasion or scratching all minerals are compared to a relative standard scale called the Mohs scale of hardness 6 fracture and cleavage go together Physical properties fracture response of crystal to breaking cleavage tendency of mineral to break along plane s of weak bonding physical properties cleavage produces flat shiny surfaces describe by geometric shape of planes angles between adjacent planes 7 physical properties density physical properties secondary special properties shown by limited minerals reaction to hydrochloric acid double refraction magnetism taste fluorescence some minerals if shine light on them will glow smell elasticity over 4000 distinct minerals rock forming minerals common minerals that make up most of the rocks of Earth s crust only 20 minerals The Silicates most important mineral groups most rock forming minerals silicon oxygen tetrahedron is the fundamental building block cleavage breakage along weak planes producing flat surfaces fracture random breaking