Raw
Diamonds from DeBeers webpageMinerals
Raw
Diamonds from DeBeers webpage
| Go to PART II: Earth Materials on this page and click on 5.1, 5.2 | |
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NOTES:
I. Minerals
A. Element- a substance composed of only one type of atom
1. Some minerals may be composed of one element such as sulfur, gold, silver, mercury.
2. A mere 12 elements account for 99.23 weight percent of the continental crust. The most abundant elements in the continental crust are:
B. Compound- 2 or more elements combined that create a new substance with unique characteristics. The elements form a repeating crystal structure that is responsible for the characteristics of the material. Examples: NaCl, CaSO4, FeO ect.
C. Minerals:
1. Minerals are naturally occurring
2. Minerals have a crystalline structure
3. Minerals are inorganic, not derived from living materials.
4. Minerals have unique chemical and physical properties
5. Minerals can be composed of one or more elements
D. Mineral Composition
1. Most of the earths crust and most minerals are made up of only a few elements: Oxygen, silicon, aluminum, iron, calcium, sodium, magnesium, potassium. See the esrt’s
2. Oxygen is the most abundant element by both mass and volume (esrt’s)
3. Silicon is the second most abundant element
E. Mineral Properties
1. Hardness- a minerals resistance to scratching
a. Hardness is a relative scale. One mineral is compared to the next and arranged according to which scratches the other. The scale is called Moh’s hardness scale:
The hardness of a mineral is one of the most diagnostic and easy tests to perform in the attempt to identify an unknown mineral. Hardness is a measure of a mineral's resistance to abrasion and reflects the atomic structure of a mineral.
Hardness is measured on the Mohs scale, identified numerically hardness of by standard minerals, from 1 (softest) to 10 (hardest):
Below is the Mohs Hardness Scale:
A mineral of a given hardness will scratch a mineral of a lower number. With a systematic approach, you can use minerals of known hardness to determine the relative hardness of any other mineral.
2. Color- color is not a very good way to identify a mineral. Many minerals have similar colors, but are completely different. Take for example FeS (Iron Pyrite “fools gold”) and real gold Au a native metal mineral.
3. Streak- the color of a mineral when it is in a powder form. To powder a mineral a piece of porcelain is used. The mineral rubbed along the porcelain and the true color is revealed. Often a minerals color and streak are very different.
4. Luster- the appearance of a mineral in light. We will consider two main types of luster: metallic and non-metallic. Metallic minerals look like, yes you guessed it metal. Read this for more detailed information on luster.
5. Cleavage- the tendency for a mineral to break and create a smooth face. Crystal cleavage is a smooth break producing what appears to be a flat crystal face. Here are a few rules about cleavage. First cleavage is reproducible, meaning that a crystal can be broken along the same parallel plane over and over again. All cleavage must parallel a possible crystal face. THIS PROPERTY IS DUE TO THE INTERNAL ARRANGEMENT OF THE ATOMS MAKING UP THE MINERAL!
6. Fracture- when a mineral does not break along a smooth flat surface plane. All minerals can fracture, even minerals that cleave good. THIS PROPERTY IS DUE TO THE INTERNAL ARRANGEMENT OF THE ATOMS MAKING UP THE MINERAL!
7. Crystal shape- THE ARRANGEMENT OF THE ATOMS WITHIN THE MINERAL CAUSES MINERALS TO HAVE DISTINCT SHAPES.
8. Specific gravity- comparing a minerals density to the density of pure liquid water.
9. Density- no need for me to explain this.
F. Mineral Structure
1. Minerals have many different classes. One of the largest groups of minerals is the silicates. All silicates contain the SiO4 tetrahedron.
2. The different arrangement of the individual tetrahedrons can cause many different physical properties of silicate minerals. See the next diagrams
G. Rocks
1. Rocks are composed of minerals. A monomineralic rock contains only one mineral. Ex: Limestone (CaCO3)
2. A polymineralic rock contains more than one mineral. Ex: Granite
3. Of the 2,500 or so minerals only 20-30 are commonly found in most rocks.
Name____________________________
Exam: Rocks and Minerals Practical
Directions: Identify the rock samples. Copy the Code number down next to the sample #. If you fail to tell me the sample # you can not receive credit because I will not know which rock you are trying to identify. When stating evidence be sure to identify features unique to the type of rock you are looking at. Be sure the evidence you state is a feature of the rock type you chose. Here are some key words to help you: Fossils, intergrown crystals, deformed crystals, distorted pebbles, distorted structure, foliations, banding of minerals, clasts, porphyritic texture, mafic, felsic, intrusive, extrusive…..
1. CODE #________________
a. What type of rock is this? (Sedimentary, Igneous or Metamorphic)
:______________________________________________________________
b. State at least one piece of evidence that you used to identify the rock.
:_______________________________________________________________________________________________________________________________________________________________________________________________________________________
2. CODE #________________
a. What type of rock is this? (Sedimentary, Igneous or Metamorphic)
:______________________________________________________________
b. State at least one piece of evidence that you used to identify the rock.
:_______________________________________________________________________________________________________________________________________________________________________________________________________________________
3. CODE #________________
a. What type of rock is this? (Sedimentary, Igneous or Metamorphic)
:______________________________________________________________
b. State at least one piece of evidence that you used to identify the rock.
:_______________________________________________________________________________________________________________________________________________________________________________________________________________________
You need to know the following for the quiz:
Ø Hardness
Ø Streak
Ø Specific gravity
Ø Fluorescence
Ø magnetism
Ø Reactivity with acid
Ø Luster
Ø Mica
Ø Calcite
Ø Halite
Ø Hematite
Ø Galena
Ø Gypsum
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Sources: U.S. Geological Survey, Minerals Information Institute
Did you know that if you can't grow it, it has to be mined or recycled?
Did you know that construction of an average six-room house requires 39 tons of aggregate?
The foundation is made from limestone, clay, shale, gypsum, and aggregate.
The exterior might be brick (made from clay) or stone.
The insulation may be made of glass wool (made from silica, feldspar, and trona) or expanded vermiculite.
The interior walls are generally faced with wallboard made from gypsum.
Metal nails and screws hold the wood frame of the house together.
The roof might be asphalt shingles covered with bits of colored silica
The fireplace may have a steel lining made from iron ore and be faced with brick or stone
The sewer pipes are made of clay or iron
The electrical wiring is made of copper or aluminum
Sinks and toilets are commonly porcelain made from clay
Plumbing fixtures are made of brass (copper and zinc) or stainless steel (nickel and chrome).
Rain gutters are made of aluminum
Paint is manufactured with mineral fillers (clay and limestone) and pigments (from various minerals)
Door knobs, locks, and hinges are made of brass or steel (copper, zinc, and iron ore)
Mortgages are printed on paper made from wood or cloth fibers, but filled with clay to give a nice smooth printing surface.
Did you know that in Pre-Columbian times, indigenous people in North America mined turquoise, jet, opal, copper, silver, coal, obsidian and other igneous rocks, asbestos, salt, and sodium sulfate, as well as other minerals? Turquoise, jet, opal, copper, and silver were mined mostly for decorative use. Coal was mined for fuel. Obsidian and other igneous rocks were mined to make projectile points, mortars and pestles, grinding stones, stone axes, and other tools. Clay and asbestos were mined to make pottery; salt was used as a preservative and for flavoring; and sodium sulfate was used as a purgative.
Did you know that many of the clear juices, such as apple juice, and the wines that you may drink are filtered through skeletons? The skeletons of diatoms, microscopic single-celled plants that live in fresh or sea water, are extremely intricate and are made of silica. When large numbers of these skeletons are gathered, cleaned, and packed together to form a filter, their intricate geometry will trap the very small particles that make juices or wines look cloudy.
Of the 193,000 metric tons of gold discovered to date, 62% is found in just four countries on earth. All the gold discovered thus far would fit in a cube 22 meters on a side.
Of the 1,740,000 metric tons of silver discovered to date, 55% is found in just four countries on earth. All the silver discovered thus far would fit in a cube 55 meters on a side.
Of the 1.52 billion metric tons of copper discovered to date, 56% is found in just four countries on earth. All the copper discovered thus far would fit in a cube 550 meters on a side.
Over 50% of all the zinc and lead discovered to date has been found in just four countries on earth.
There are about 10 million passenger cars made each year in the United States. Natural resources are used to make each of the 15,000 parts in each of those cars.
In the average 3,000-pound car there are 139 pounds of aluminum, 28 pounds of copper, and 20 pounds of zinc.
The automobile industry uses 17% of the 12 million tons of steel produced in the U.S. each year.
Catalytic converters for cars used 660,000 troy ounces of platinum in 1986. Platinum is also used in the synthesis of MTBE, a gasoline additive to replace lead and reduce automobile carbon monoxide emissions.
Roads and highways are made from gravel, asphalt, and cement; all produced from minerals.
Glass is made from silica sand and limestone, both of which have to be mined.
The mineral barite is used to add weight to oil well drilling mud to keep oil in the drill hole and prevent oil from gushing out of the hole.
Various clays have replaced asbestos in many construction and industrial applications.
Clays are used in hazardous waste disposal to solidify organic waste and salt solutions, and to create impermeable barriers to encase the waste.
Clays are used in water treatment to selectively absorb organic contaminants and to remove paint residue from water used in industrial processes.
Diatoms, microscopic single-celled plants that live in fresh or sea water, have extremely intricate shells made of silica. When large numbers of these shells are deposited, diatomite is formed. When diatomite is cleaned and packed to form a filter, the intricate geometry of the shells will remove impurities as small as 0.1 micron from the water without the use of chemicals. Diatomite can also be used as a non-chemical insecticide, the sharp silica shells cut and shred the insects.
A microcoating of gold on glass reflects solar energy and reduces the electrical demand of air conditioning.
Limestone is used in agriculture to stabilize soil and control pH.
Limestone is used to neutralize sulfur oxide gases from industrial sources
Limestone is used to solidify and neutralize PCB sludge and to stabilize sludge from sewage and desulfurization plants
Limestone removes phosphorus and nitrogen, controls odor, kills bacteria, and aids in the clarification of waste water. Limestone will also neutralize acid rain and acid drainage.
Lithium is used in high energy batteries for such things as computers and propulsion of electric cars.
Silver is used to kill bacteria in water purification systems.
Sulfur is used as a phosphor in low-energy lighting.
Zeolite minerals are used to stabilize ammonium and potassium in soil for agriculture; to improve air quality they are used in air filtration, odor control, and purification of gases and air by selectively adsorbing gases such as ammonium, hydrogen sulfide, carbon monoxide, carbon dioxide, nitrogen, formaldehyde, and mercaptan; zeolites are used in hazardous waste cleanup to contain heavy metals and nuclear waste and to remove ammonium in water treatment.
Approximately 90% of the phosphate mined in the world today goes into fertilizer for production of food. The U.S. is now the world's leading producer of phosphate, fully providing for our own requirements and a small amount for export. Morocco will become the leading producer in the not-too-distant future.
Mineral elements provide the color in fireworks. Barium produces bright greens; strontium yields deep reds; copper produces blues; and sodium yields yellow. Other colors can be made my mixing elements; strontium and sodium produce brilliant orange; Titanium, zirconium, and magnesium alloys make silvery white; copper and strontium make lavender. Gold sparks are produced by iron filings and small pieces of charcoal. Bright flashes and loud bangs come from aluminum powder.
To maintain our standard of living, each person in the United States requires over 48,000 pounds of minerals each year:
12,528 lb. of stone
9,385 lb. of sand and gravel
888 lb. of cement
280 lb. of clays
418 lb. of salt
309 lb. phosphate
729 lb. of nonmetals
589 lb. of iron ore
73 lb. of aluminum
24 lb. of copper
14 lb. of lead
13 lb. of zinc
6 lb. of manganese
.0285 T oz. gold
20 lb. of other metals
PLUS:
7,578 lb. petroleum
7,643 lb. coal
7,985 natural gas
1/4 lb. uranium
Source: Minerals Information Institute
Gold plays an important role in keeping American pilots safe. Gold us used in microelectronic circuitry in escape mechanisms, parachutes, and air-survival radios. Gold is the best metal to use in these applications because it does not corrode, crumble, or tarnish whatever the conditions; it is unaffected by moisture, oxygen or ordinary acids, and is virtually indestructible.
Gold helps save lives on the nation's roads. More than 30 million automobiles are equipped with air bag systems that have gold-coated electrical contacts to ensure that the system will work flawlessly for the life of the car.
Hospitals and office buildings are monitored by gold-coated infrared sensors to detect unhealthy buildup of carbon monoxide and other indoor pollutants.
In the space program, gold's ability to reflect infrared radiation helps shield astronauts, sensitive electronic equipment, circuitry, and protect the tether that secures astronauts on spacewalks.
Magnetite is an iron oxide mineral that is magnetic
Fool's Gold can be one of three minerals; the most common mineral mistaken for gold is pyrite, chalcopyrite may also appear gold-like, and weathered biotite mica can mimic flake gold.
What is the meaning of the karat mark on gold jewelry? The fineness of jewelry gold is stated as the number of parts in twenty-four that are gold. Thus, 24 karat gold is pure gold; 12 K would be an alloy that is half gold and half copper or other metals.
White gold was originally developed to imitate platinum, and is usually an alloy containing 25% nickel and zinc. If stamped 18 karat, it would be 75% pure gold.
Sterling silver is the standard of quality for articles containing 92.5% silver and 7.5% copper.
Galvanizing is the process of dipping steel in molten zinc to prevent rusting.
Until 1886, aluminum was considered a rare metal and a chemical curiosity. Researchers in the U.S. and France independently discovered the continuous electrolytic reduction process which is used to make aluminum metal from the aluminum ore, bauxite.
Pewter can be a variety of alloys. Modern pewter is 93% tin, 6% antimony, and 1% copper. Other metals that have been used in pewter include lead, bismuth, and zinc.
Vermiculite, mica-like minerals that expand or exfoliate when heated to between 1,400 and 2,000 degrees, expand due to the expansion of water as it changes to steam between the layers.