Rocks & Minerals

Minerals Saddle-shaped pink dolomite crystals.

What is a Mineral? Naturally Occurring Naturally Occurring Inorganic Inorganic Solid Solid Definite Chemical Formula Definite Chemical Formula Definite Crystal Structure Definite Crystal Structure Galena Beryl

Naturally Occurring Formed by natural processes not in the laboratory. Formed by natural processes not in the laboratory. - Is an Ice Cube a mineral? - Is an Ice Cube a mineral? - Is the ice on the wind- - Is the ice on the wind- shield of a car a mineral? - What about the ice in - What about the ice in your refrigerator? your refrigerator?

Inorganic Formed by inorganic processes; not living Formed by inorganic processes; not living Does not contain chains of carbon atoms Does not contain chains of carbon atoms

Solid Not gas or liquid Not gas or liquid H 2 O as ice in a glacier or a snowflake is a mineral, but liquid water in the ocean is not. H 2 O as ice in a glacier or a snowflake is a mineral, but liquid water in the ocean is not. The element mercury is a metal that’s a liquid at room temperature/pressure. Liquid mercury is NOT a mineral! The element mercury is a metal that’s a liquid at room temperature/pressure. Liquid mercury is NOT a mineral!

Definite Crystal Structure Highly ordered atomic arrangement of atoms in regular geometric patterns Highly ordered atomic arrangement of atoms in regular geometric patterns 8 Tourmaline K-spar Fluorite Pyrite Kyanite Fluorite

Crystal Structure of Ice

Definite Chemical Formula Minerals are expressed by a specific chemical formula Minerals are expressed by a specific chemical formula -Gold (Au) -Calcite (CaCO 3 ) -Quartz (SiO 2 ) -Pyrite (FeS 2 )

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? Crystallize from magma and lava. Precipitate from water due to evaporation. Olive crystallizes from mafic magma.

How Are Minerals Identified? Color Color Luster Luster Hardness Hardness Streak Streak Density Density Crystal Shape Crystal Shape Cleavage and Fracture Cleavage and Fracture Special Properties Special Properties

Color Usually the first and most easily observed Usually the first and most easily observed -Some minerals are always the same color -Some minerals can have many colors QUARTZROSE QUARTZSMOKY QUARTZ

Luster General appearance of a mineral surface in reflected light General appearance of a mineral surface in reflected light Glassy-Obsidian

Hardness Resistance to scratching by different items; “scratchability” Resistance to scratching by different items; “scratchability” Mohs Hardness Scale >2 fingernail 3 penny 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 2) Gypsum 3) Calcite 4) Flourite 5) Apatite 6) Feldspar 7) Quartz 8) Topaz 9) Corundum 10) Diamond Softest Hardest

Streak The color of a finely powdered mineral The color of a finely powdered mineral Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate) Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate)

Density The amount of matter in a given space (Mass/Volume) 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 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 Cleavage is the tendency of a mineral to split or crack along parallel or flat planes Rhombohedral cleavage forms “smushed” cubes (calcite). Octahedral Cleavage forms bi-pyramids (Fluorite) One direction of cleavage = basal cleavage (biotite mica).

Cleavage and Fracture Fracture occurs when a mineral breaks at random lines instead of at consistent cleavage planes. Fracture occurs when a mineral breaks at random lines instead of at consistent cleavage planes. Conchoidal fracture is what gives quartz, obsidian, chert, and flint those super- sharp edges! Conchoidal fracture is what gives quartz, obsidian, chert, and flint those super- sharp edges! Quartz has no cleavage and instead exhibits conchoidal fracture.

Special Properties Magnetism (Magnetite) Magnetism (Magnetite) Optical Properties (calcite and ulexite) Optical Properties (calcite and ulexite) Glowing under ultraviolet light (Fluorite) Glowing under ultraviolet light (Fluorite) Salty taste (Halite) Salty taste (Halite) Smell (Sulfur) Smell (Sulfur) Reaction to weak acids (Calcite) Reaction to weak acids (Calcite) Magnetite

Economic Importance of Minerals Minerals are in many things we see and use everyday such as; bricks, glass, cement, plaster, iron, gold 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: 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 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 cemented together squeezed and heated together squeezed and heated together melted and cooled together. melted and cooled together.

Types of Rocks Igneous Igneous Sedimentary Sedimentary Metamorphic Metamorphic

Igneous Rocks Most igneous rocks are produced deep underground by the cooling and hardening of magma 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 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 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 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. 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 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 Composition-refers to the minerals that make up the rock Texture-shape, size, arrangement and distribution of 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 Extrusive- Formed from lava; volcanic Intrusive- Formed deep within the earth Intrusive- Formed deep within the earth Obsidian Pumice Granite

Textures Glassy Glassy Fine-grained Fine-grained Coarse-grained Coarse-grained Porphyritic Porphyritic ObsidianGranite Basalt

Classification of Sedimentary Rocks Clastic Rocks- Made of the fragments of previously existing rocks Clastic Rocks- Made of the fragments of previously existing rocks Organic Rocks- Come from organisms Organic Rocks- Come from organisms Chemical Rocks- Formed by inorganic processes such as evaporation Chemical Rocks- Formed by inorganic processes such as evaporation

Clastics Rocks Conglomerate Conglomerate Sandstone Sandstone Mudstone Mudstone

Organic Rocks Limestone Limestone CoquinaFossiliferous Limestone

Chemical Rocks Limestone Limestone

Metamorphic Rocks Foliated- Parallel alignment of flattened mineral grains and pebbles Foliated- Parallel alignment of flattened mineral grains and pebbles Unfoliated-Rocks that are not banded and do not break into layers Unfoliated-Rocks that are not banded and do not break into layers

Foliated Gneisse

Unfoliated Marble

Distribution of Rocks in the U.S.