Rocks & Minerals PDF

Rocks & Minerals Minerals  What is a Mineral? Naturally Occurring Inorganic Solid Definite Chemical Formula Definite Crystal Structure  Naturally Occurring Formed by natural processes not in the laboratory - Is an Ice Cube a mineral? - Is the i...

Rocks & Minerals Minerals  What is a Mineral? Naturally Occurring Inorganic Solid Definite Chemical Formula Definite Crystal Structure  Naturally Occurring Formed by natural processes not in the laboratory - Is an Ice Cube a mineral? - Is the ice on the windshield of a car a mineral?  Inorganic Formed by inorganic processes; not living Does not contain chains of carbon atoms  Solid Not gas or liquid -H2O as ice in a glacier is a mineral, but water is not  Definite Crystal Structure Highly ordered atomic arrangement of atoms in regular geometric patterns Apatite Feldspar Diamond Quartz 8  Definite Chemical Formula Minerals are expressed by a specific chemical formula -Gold (Au) -Calcite (CaCO3) -Quartz (SiO2) -Pyrite (FeS2) Composition of the Earth’s Crust  Eight Elements that make up over 98% of Earth’s Crust -Oxygen (O) -Silicon (SI) -Aluminum (Al) -Iron (Fe) -Calcium (Ca) -Sodium (Na) -Potassium (K) -Magnesium (Mg) Where Do Minerals Come From? Magma Evaporation  How Are Minerals Identified? Color Luster Hardness Streak Density Crystal Shape Cleavage and Fracture Special Properties  Color Usually the first and most easily observed -Some minerals are always the same color -Some minerals can have many colors ROSE QUARTZ QUARTZ SMOKY QUARTZ  Luster General appearance of a mineral surface in reflected light Glassy-Obsidian  Hardness Resistance to scratching by different items; “scratchability” Mohs Hardness Scale >2 fingernail 3 penny ~5 Steel of a pocket knife 5.5 Window Glass 6.6 Steel of a file 7 quartz crystal  Mohs Mineral Hardness Scale 1) Talc Softest 2) Gypsum 1 3) Calcite 5 4) Flourite 5) Apatite 9 2 6) Feldspar 6 7) Quartz 8) Topaz 3 7 9) Corundum 10 10) Diamond Hardest 4 8  Streak The color of a finely powdered mineral Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate)  Density The amount of matter in a given space (Mass/Volume)  Crystal Shape Minerals have a characteristic crystal shape resulting from the atomic packing of the atoms when the mineral is forming  Cleavage and Fracture Cleavage is the tendency of a mineral to split or crack along parallel or flat planes Fracture occurs when a mineral breaks at random lines instead of at consistent cleavage planes. BIOTITE QUARTZ Obsidian 1 Direction of Cleavage No Cleavage Conchoidal Fracture  Special Properties Magnetism (Magnetite) Glowing under ultraviolet light (Fluorite) Salty taste (Halite) Smell (Sulfur) Magnetite Reaction to HCl (Calcite)  Economic Importance of Minerals Minerals are in many things we see and use everyday such as; bricks, glass, cement, plaster, iron, gold  Every American Requires 40,000 Pounds of New Minerals per Year at this level of consumption the average newborn infant will need a lifetime supply of: -795 lbs of lead (car batteries, electric components) -757 lbs of zinc (to make brass, rubber, paints) -1500lbs of copper (electrical motors, wirings -3593 lbs aluminum (soda cans, aircraft) -32,700 lbs of iron (kitchen utensils, automobiles, buildings) -28,213 lbs of salt (cooking, detergents) -1,238,101 lbs of stone, sand, gravel, cement (roads, homes, etc.) Rocks  Rocks  Made of two or more different minerals that have been: cemented together squeezed and heated together melted and cooled together.  Types of Rocks Igneous Sedimentary Metamorphic  Igneous Rocks Most igneous rocks are produced deep underground by the cooling and hardening of magma  Sedimentary Rocks Formed from the breaking apart of other rocks (igneous, metamorphic, or sedimentary rocks) and the cementation, compaction and recrystallization of these broken pieces of rock Fact about the Mississippi River Did You Know? The Mississippi River carries an average of 436,000 tons of sediment each day It moves an average of 159,000,000 tons of sediment a year  Metamorphic Rocks Formed from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, igneous, or even another metamorphic rock.  The Rock Cycle The diagram of the rock cycle shows how the earth's rocks are changed again and again  Classification of Igneous Rocks Composition-refers to the minerals that make up the rock Texture-shape, size, arrangement and distribution of minerals that make up the rock  Composition Extrusive- Formed from lava; volcanic Obsidian Pumice Intrusive- Formed deep within the earth Granite  Textures Glassy Coarse-grained Obsidian Granite Fine-grained Porphyritic Basalt Granite  Classification of Sedimentary Rocks Clastic Rocks- Made of the fragments of previously existing rocks Organic Rocks- Come from organisms Chemical Rocks- Formed by inorganic processes such as evaporation  Clastics Rocks Conglomerate Mudstone Sandstone  Organic Rocks Limestone Coquina Fossiliferous Limestone  Chemical Rocks Limestone  Metamorphic Rocks Foliated- Parallel alignment of flattened mineral grains and pebbles Unfoliated-Rocks that are not banded and do not break into layers Foliated Gneisse Unfoliated Marble Distribution of Rocks in the U.S.