Chapter 1 Minerals of the Earth’s Crust S hussey modified mdeppe 2010

Geology The study of the origin, history, and structure of the Earth. Geology-

Meteorology- The study of the Earth’s atmosphere in relation to weather and climate.

Seismology- The study of Earthquakes.

Astronomy- The study of the universe.

Paleontology- The study of fossils.

Oceanography- The study of the sea

Both of these substances are made of carbon. Why are they so different?

What is a mineral A naturally formed, inorganic solid that has a definite crystalline structure

Minerals Form in nature Always a solid Not made of living things Have a specific crystal structure

Elements are pure substances that cannot be broken down into simpler substances by chemical means

Atom is the smallest part of an element that has all the properties of that element

Compound Is a substance made of two or more elements that have been chemically joined. An example is Halite. It is formed by Sodium and Chlorine joining.

Native Element Elements that are composed of only one element Examples are gold and silver. They do not combine.

The most common classification of minerals is based on chemical composition.

Two Groups of Minerals 1.silicate minerals-contain the elements silicon and oxygen Silicon and oxygen are the two most common elements in the Earth’s crust. Silicate minerals make up more than 90% of the minerals in the Earth’s crust.

2.Nonsilicate Minerals-minerals that do not have the combination of the elements silicon and oxygen.

Section 2 Identifiying Minerals

Properties of minerals Color Luster Streak Cleavage and Fracture Hardness Density

Color Color alone is not enough to identify a mineral…all these samples of quartz are different colors

Luster- The way light reflects from the surface of a mineral Minerals can be shiny (like metal) or dull

Streak- The color of the powder made when a mineral is scratched against a tile The streak shows the true color of the mineral.

Cleavage- breaks along smooth or flat surfaces Fracture-breaks uneven How a mineral splits or breaks

Hardness Use Mohs scale to determine how hard a mineral is. The hardest mineral is a diamond, the softest is talc.

How Diamonds Form Diamond Mining Big Diamond

Density the measure of how much matter is in a given amount of space It is usually measured in grams/cubic centimeter.

Special Properties Some properties are specific to only a few types of minerals. Those properties are: 1.Fluorescence (glow) 2.Chemical Reaction (fizz) 3.Optical Properties (double image) 4.Magnetism 5.Taste 6.Radioactivity (detected by geiger counter)

Section 3: The Formation, Mining, and Use of Minerals The environment in which the mineral forms determines the mineral’s properties.

Evaporating Salt Water When a body of salt water dries up, minerals are left behind. Examples are gypsum and halite

Limestone Surface water and ground water carry dissolved materials into lakes and seas, where they crystallize on the bottom. Examples are calcite and dolomite

Metamorphic Rocks This is when changes in pressure, temperature, or chemical make-up alter a rock. Examples are calcite, garnet, graphite, mica, magnetite, and talc.

Hot-Water Solutions Groundwater works its way downward and is heated by magma. Dissolved metals and other elements crystallize out of the hot fluid to form new minerals. Examples are gold, copper, sulfur, pyrite, and galena

Pegmatites As magma moves upward, it can form these teardrop shaped bodies. Examples are topaz and tourmaline

Plutons As magma rises upward, it can stop before it reaches the surface causing it to cool slowly. Examples are mica, feldspar, magnetite, and quartz

Mining ore-a mineral deposit large enough and pure enough to be mined for profit

Rocks and minerals are removed from the ground by one of two methods 1.Surface mining-when mineral deposits are located at or near the surface of the Earth Types of surface mines are: open pits, surface coal mines, and quarries

Open Pit Mines Used to remove large deposits near the surface that are valuable like gold and copper Look at figure 1 on page 14

Surface Coal Mining Is used to mine coal near the surface It is also known as strip mining.

Coal Strip Mine Career in Mining Life of a Miner History of the Gold Rush

Quarries Are open pit mines that are used to mine building stone, crushed rock, sand, and gravel

Subsurface Mining -used when mineral deposits are located too deep within the Earth to be surface mined

Disadvantages to Mining Destroys habitats of plants and animals Pollutes water sources

Ways to Reduce Harmful Effects of Mining 1.Reclamation-a process to return land to its original state or better This has been required by law since mid- 1970’s. 2. Reduce use by recycling

Reclamation Video You tube

The Use of Minerals Look at page Table 1 Types of Minerals: 1. Metallic Shiny Light cannot pass through Can be processed so they do not rust Can be made into different shapes Very good for aircraft, automobiles, computers, and spacecraft

2. Nonmetallic Minerals shiny or dull light passes through them Good insulators of electricity Widely used in the industry Examples are sand and gravel

3. Gemstones (nonmetallic) Highly valuable Color is the most important characteristic of a gemstone (makes it valuable) Must be durable, so they can be cut Mass is expressed in carats One carat = 200 mg. Examples-: diamond, ruby, sapphire, and emerald

Rocks Rocks are the building blocks of the Earth’s Crust Rocks are classified by how they are formed There are 3 types of rocks Can you name them?

Rock Cycle Over time rocks cycle between all three rock types.

Igneous Rocks Form when rocks cool and crystallize and harden.

Two Types of Igneous Rocks Those that cool ABOVE ground *They come out of a volcano They are pushed out (or extruded) of the ground EXTRUSIVE Those that cool BELOW ground They become rocks when magma cools slowly underground INTRUSIVE

Examples of Igneous Rock obsidian basalt pumice granite gabbro

Two Types of Igneous Rocks Extrusive Obsidian Cools quickly when it comes out of a volcano Small crystals Intrusive Granite Cools slowly underground Large crystals

Sedimentary Rock Forms at Earth’s surface when sediment (small pieces of rocks, minerals, organic material) hardens into rock.

Types of Sedimentary Rock sandstone limestone shale

Metamorphic Rocks Forms when heat and pressure are applied to existing rocks

Types of Metamorphic Rock schist slate marble gneiss

Compare and Contrast Rocks & Minerals

Reference