Identifying Minerals

• Luster describes how a mineral reflects light and can be metallic or nonmetallic.
  • Metallic luster shines like gold, silver, or copper.
  • Nonmetallic luster does not shine like gold, silver, or copper.
• Streak refers to the color of a mineral's powder left behind on unglazed ceramic tile.
• Crystal form refers to how crystals form based on the arrangement of atoms.
• Cleavage/Fracture describes how a mineral breaks.
  • Cleavage is evident when a mineral breaks evenly due to weak bonds, such as in cubic or thin sheet formations.
  • Fracture occurs when a mineral breaks unevenly.
• Specific Gravity indicates the density of a mineral in comparison to the density of water.
  • This test is accurate but cannot occur in the field.
• Special properties help identify minerals.
  • An acid test uses hydrochloric acid (HCl) on calcite to identify calcium carbonate (CaCO3).
  • Smell - sulfur has a distinct smell.
  • Taste - halite tastes salty
  • Fools Gold - Pyrite
  • Magnetism indicates a mineral contains magnetite.
• Resources are limited and can be either renewable or nonrenewable, each with advantages and disadvantages.
• Modern living standards rely on using both renewable and nonrenewable resources extensively.
• Extracting and using any resources carries an environmental cost, which must be weighed against economic benefits.
• Renewable resources can be replaced by nature at a rate close to their rate of use.
  • Examples are: vegetation, sunlight, wind, biomass, geothermal, and water.

Solar

- Advantages: Generates electricity and requires little maintenance.
- Disadvantages: Generates no energy at night or when it is cloudy and has an expensive initial investment.

Wind

- Advantages: Wind is free.
- Disadvantages: Good wind sites are usually far from cities and wind is not constant.

Water

- Advantages: Produces at a constant rate and can be turned on or off.
- Disadvantages: Dams are expensive to build and flood large areas upstream, destroying the environment.

• Nonrenewable resources are replenished slowly, if at all.
  • Examples are fossil fuels and minerals.

Fossil Fuels

- Advantages: Are cheap and easy to use once extracted and create huge amounts of energy (natural gas, oil, and coal).
- Disadvantages: Burning them causes pollution, and greenhouse gases get formed.

Minerals

- Advantages: Minerals are used by people daily and brings jobs.
- Disadvantages: Extraction can be noisy and damage the environment. Some companies will attempt to restore the landscape after finishing.

• Major mineral and rock resources in Virginia include:
  • Coal for energy.
  • Gravel and crushed stone for road construction.
  • Limestone for making concrete.
• Virginia depends on fossil fuels, especially coal (non-renewable), for most of its energy, but biomass is their number-one renewable energy source used.
• Density = Mass/Volume.
• Water displacement is equal to big volume - small volume.
• The ozone layer is in the atmosphere, which protects against ultraviolet radiation.
• Topo Maps show lines that represent lines of equal elevation (steep vs. gentle slope)
• Common elements found in Earth's continental crust include:
  • Silicon (Si) at about 28%.
  • Oxygen (O) at about 47%.
• Mineral characteristics include:
  • Naturally occurring formation (not man-made).
  • Inorganic composition.
  • Solid state.
  • A definite chemical composition (unique combination of elements).
  • Crystalline shape (arrangement of atoms).
• Mineral formation occurs through magma (crystallization); how magma cools and where it cools determines crystal size:
  • Near the surface = small crystals.
  • Deep underground = large crystals.
  • The quicker it cools, the smaller the crystals.
  • Crystals need heat and time (deep inside the Earth) to grow.
• Mineral families (groups) are based on their chemical composition.
  • Silicates contain silicon (Si) and oxygen (O).
  • Carbonates contain the carbonate compound CO3.
  • Oxides contain oxygen (O) and metal.
  • Sulfates/Sulfides contain sulfur (S) bonded to other elements.
  • Native elements contain one element and exist in pure form.
• Minerals are used in a variety of ways:
  • Aluminum in transportation, packaging, cans, and aircraft.
  • Silica and Quartz in electronics, glass, gemstones, and precision instruments.
  • Copper in electrical applications, plumbing, and roofing.
  • Graphite in pencils.
  • Diamonds in jewelry and drilling tools.
• Mineral identification tests:
  • Color: minerals can be many colors (least reliable test).
  • Hardness: classified by whether they can scratch each other (most reliable test).
    • Mohs Hardness Scale goes from 1-10 (1=softest & 10=hardest).