coppergoldsilver
TRANSCRIPT
Section 1: What is a Mineral?
A mineral is a naturally formed, inorganic solid that has a definite crystalline structure.
Mineral Structure
Elements are pure substances that cannot be broken down into simpler substances by ordinary chemical means.
All minerals contain one or more of the 92 naturally occurring elements
4 Questions to determine if an object is a mineral:
1. Is it a solid?
Minerals can’t be gases or liquids
2. Is it nonliving material?
A mineral is inorganic, meaning it isn’t made of living things
3. Does it have a crystalline structure?
Minerals are crystals, which have a repeating inner structure that is often reflected in the shape of a crystal
Minerals generally have the same chemical composition throughout
4. Is it formed in nature?
Crystalline materials made by people aren’t classified as minerals
Atoms and Compounds
An atom is the smallest part of an element that has all the properties of that element
Minerals are made up of atoms of one or more element
Most minerals are made of compounds of several different elements
A compound is a substance made of two or more elements that have been chemically joined, or bonded
A mineral that is composed of only one element is called a native element
Crystals
Solid, geometric forms of minerals produced by a repeating pattern of atoms or molecules that is present throughout the mineral are called crystals
A crystal’s shape is determined by the arrangement of the atoms or molecules within the crystal
The arrangement of atoms or molecules in turn is determined by the kinds of atoms or molecules that make up the mineral
Each mineral has a definite crystalline structure
Two Groups of Minerals
The most common classification of minerals is based on chemical composition. They are divided into two groups based on their chemical composition: Silicate minerals or Nonsilicate Minerals
Silicate Minerals: Silicon and oxygen are the 2 most common
elements in the Earth’s crust
Minerals that contain a combination of silicon and oxygen are called silicate minerals
They make up more than 90% of the Earth’s crust and the rest is made up of nonsilicate minerals
Nonsilicate Minerals:
Minerals that do not contain a combination of the elements silicon and oxygen form a group called the nonsilicate minerals
6 Major Classes of Nonsilicate Minerals:
1. Native elements – made of only one element
Examples: copper, gold, and silver
Used in communications and electronics equipment
COPPER GOLD SILVER
2. Carbonates – contain combinations of carbon and oxygen
Example: Calcite
Used in cement, building stones, and fireworks
3. Halides – form when fluorine, chlorine, iodine, or bromine combine with sodium, potassium or calcium
Example: Fluorite
Are used in the chemical industry and in detergents
4. Oxides – formed with an element combines chemically with oxygen
Example: Corundum
Used to make abrasives, aircraft parts, and paint
5. Sulfates – contain sulfur and oxygen
Example: Gypsum
Used in cosmetics, toothpaste, cement, and paint
6. Sulfides – contain one or more elements, such as lead, iron, or nickel, combined with sulfur
Example: Galena
Used to make batteries, medicines, and electronic parts
Bellringer: How do you describe what you see, feel,
and smell?
List as many phrases as you can to describe each mineral given.
Organize your phrases into different categories, such as color, shape, and luster.
Do any minerals have a specific smell?
Color The same mineral can come in a variety of colors
Impurities, exposure to air, etc can change colors of minerals and therefore isn’t the best way to identify minerals
Luster The way a surface reflects light is called
luster
When you say something is shiny or dull, you are describing luster
If a mineral is shiny, it has a metallic luster
If the mineral is dull, its luster is either submetallic or nonmetallic
Streak The color of a mineral in powdered form is
called the mineral’s streak.
Streak can be found by rubbing the mineral against a piece of unglazed porcelain called a streak plate
The mark left on the plate is called the streak
Streak is not affected by air or water so it is more reliable than using color in identifying a mineral
Cleavage and Fracture
The way a mineral breaks is determined by the arrangement of its atoms
Cleavage is the tendency of some minerals to break along smooth, flat surfaces
Fracture is the tendency of some minerals to break unevenly along curved or irregular surfaces
Hardness
A mineral’s resistance to being scratched is called hardness
Use Mohs hardness scale to determine hardness
The greater a mineral’s resistance to being scratched it, the higher the mineral’s rating is
Use a reference material to try and scratch your mineral. If the reference mineral scratches your mineral, the reference mineral is harder than your mineral
Density
Density if the measure of how much matter is in a given amount of space
It is a ratio of an object’s mass to its volume
Measured in grams per cubic centimeter.
Measured in grams per cubic centimeter (g/cm3)
The ratio of an object’s density to the density of water is called the object’s specific gravity
Chemical Reaction
Calcite will become bubbly, or “fizz” when a drop of weak acid is placed on it
Calcite in Vinegar
Minerals form in a variety of environments in the Earth’s crust
The environment in which a mineral forms will determine it’s properties
Environments may be on or near the Earth’s surface or deep beneath the Earth’s surface
Mining
Geologists use the term ore to describe a mineral deposit large enough and pure enough to be mined for profit
Rocks and minerals are removed by one of two methods – surface mining or subsurface mining
Surface Mining: Types of surface mines include open pits,
surface coal mines, and quarries
Open pit mining is used to remove large, near surface deposits of economically important minerals such as gold and copper.
Surface coal mines are sometimes used as strip mines because the coal is removed in strips that may be as wide as 50 meters and as long as 1 kilometer.
Quarries are open pits that are sued to mine building stone, crushed rock sand and gravel.
Subsurface Mining
This method is used when mineral deposits are located too deep within the Earth to be surfaced mined
Often requires passageways be dug into the Earth to reach the ore
If a mineral deposit extends deep within the Earth, a vertical shaft is sunk which my connect a number of passageways that intersect the ore at different levels
Responsible Mining
Mining gives us the minerals we need, but it also creates a lot of problems like destruction of habitats and pollution of water sources.
Mine Reclamation One way to reduce the potential harmful effects of
mining is to return the land to its original state after the mining is completed
The process by which land used for mining is returned to its original state or better is called reclamation
Reclamation has been required by law since the mid 1970s
We can also help by reducing our need for minerals by recycling many mineral products we use, like aluminum
A Reclaimed mine site, one of my favorite reclaimed mine sites. This is a former Limestome Quarry, located in central Florida. It was reclaimed as a Golf Course, with a slope of 131 and is so difficult to play it is truly great, if your shots are VERY accurate. As you can see, even the fairways slope in every direction, and the Rough, well they rate a 10.
Reclamation of a mine site in progress, note the silt fences (rows of material that look like a fence). These are to prevent any solid particulates from the disturbed soil from entering the water through runoff from rainfall. Modern mining companies take every precuation to ensure the preservation of the natural resources of the community in which they reside and operate
The Use of Minerals
Metallic Minerals
Have shiny surfaces, do not let light pass through them and are good conductors of heat and electricity
Can be processed into metals that are strong and do not rust
Can be pounded and pressed into various shapes or stretched thinly without breaking
Properties make them desirable for use in aircraft, automobiles, computers, communications and electronic equipment and spacecraft
Nonmetallic Minerals
Have shiny or dull surfaces, may let light pass through them and are good insulators of electricity.
Some of the most widely used minerals in industry
Gemstones Nonmetallic minerals are highly valued for their
beauty and rarity rather than their usefulness.
Include diamond, ruby, sapphire, emerald, aquamarine, topaz and tourmaline
Color is the most important characteristic
Must also be durable to withstand polishing
The mass is represented with a carat.