MINERALS IN EVERYTHING

AKS 16b2, b3 The student will investigate the role of minerals in rock formation and discuss the importance of mineral resources to our society.

EQ: What is a mineral?EQ: What is the difference between a rock and a mineral?EQ: Why are minerals important resources for our society?

Vocabulary

• Mineral • Inorganic – Organic• Crystal Structure• Atom• Element• Chemical Compound• Mohs hardness scale

• Color• Streak• Luster• Density• Cleavage• Fracture• Fluorescence

Think About It.....

And this...

How do we use minerals and metals?

The average American house contains slightly more than a quarter of a million pounds ofminerals and metals (129 million housing units existing in the country in 2009). Each unit requires insulation (silica, feldspar and trona), roofing (silica sands, limestone and petroleum), and hardware (iron, zinc, copper, steel, brass). Glass windows are made of trona, silica sand, limestone and feldspar. Foundations consist of concrete made from sand, gravel and cement. Cement is made of limestone, bauxite, clay, shale and gypsum. The concrete is reinforced with steel rods.

More than 100 billion aluminum beverage cans are produced each year; about 63% arerecycled.

More than 1.4 billion movie tickets are sold each year, requiring energy fuels to heat and coolthe audience, operate the projectors, and to provide the snacks at the 39,233 theater screensin the U.S.

280 million personal computers were in use in 2009 and there were 1.28 billion cell phones sold worldwide, each containing about $1 worth of gold plus 42 other minerals and metals.

Eighty-eight percent of the electricity used in the U.S. is generated by fuels obtained by mining:45% from coal; 23% from natural gas; 20% from nuclear power. Only 7% is generated by hydro, with another 5% from petroleum, wood, wind, other gasses, geothermal, solar, and other resources.

It’s Your Turn -- Can you identify the these?

And these?

Definition of a MineralMinerals are: • Naturally occurring• Solid• Inorganic• Crystal structure • Chemical Compound

Activity: Write a sentence using the first letter of the BIG 5 to remember the definition.

Break it down...Naturally Occurring, Solid, and Inorganic

• Naturally Occurring = found in Nature, not man-made

• Solid = not a liquid or gas

• Inorganic = Non-living material (not an animal or plant; these are organic, living materials)

Break it down...Crystal Structure

• repeating pattern of flat sides and sharp edges and corners (like boxes)

Chalcedonies include many types of cryptocrystalline quartz gems and feature a number of different colors. Geologists can tell a chalcedony from the arrangement and structure of its crystals.

The needle-like crystals of this mesolite deposit from India give it a dandelion's form. Its crystalline structure formed inside a bubble of volcanic gas as igneous rock cooled.

Break it down...Chemical Composition

Everything in this world can be broken down into small structures called atoms (invisible to the eye) The world is made up of different kinds of atoms, called elements. Every object, living and non-living, has its own recipe. The ingredients in the recipe are different amounts of different elements.

In Minerals, • The elements (ingredients) are always the same• Minerals are made up of compounds (mixtures of elements)Compounds = 2 or more elements combined to make a completely new product with new characteristics.

Compounds made these...

The mineral malachite contains the elements copper, hydrogen, carbon, and oxygen. This malachite from a Zambian mine seems to take the form of rounded peas. It is found in deposits of copper ore and gets its name from the Greek word for green; malachite ranges from light to dark green.

The mineral gypsum contains calcium sulfate ( a compound of calcium, sulfur, oxygen) and water. The gypsum precipitates out of water in the cave, creating these petal-like forms over time.

Nature’s Method of Making MineralsThe earth uses gravity to generate heat and pressure which sorts minerals by density. Later, chemical bonds form which also create different densities of rocks. Gravity then does more sorting by pulling the more dense objects closer to the earth's core.Volcanoes are nature's method of naturally refining and sorting minerals. Precious minerals such as copper, silver, gold, and iron are in solution within the magma, which is deep within the earth. In solution, these minerals are in such low concentrations that they cannot be mined unless the magma is to harden.Water now becomes very important in the smelting process within the earth. Many of the most important mines in the early history of civilization such as Cyprus, relied upon copper for tools. Surface water and precipitation naturally seep into the earth's crust as the magma cools and openings form. The cooling and condensing of the magma create the cracks, fissures, and vents produced by the seeping water. This can occur in a surface volcano or an underwater "smoker". The water bonds to the copper in solution, and then carries the precious mineral back up the cracks, fissures or vents where it then hardens. The mineral is now in a higher concentration than it was in the magma. Ancient miners did not understand this process within the earth, but they understood that if they dug a horizontal shaft into a vent or fissure at the right depth they would find copper. At another depth they would find silver. They became experts in understanding how to get Mother Earth to yield her concentrated mineral. They found that some minerals were found in association due to similar densities, such as platinum and iron deposits. Prospectors in search of precious minerals found that the most convenient locations to find precious minerals were in the vents of ancient volcanoes.

The Volcano Connection

How do you identify minerals?

Hardness Color Streak Luster Density Crystal Systems Cleavage Fracture

Every mineral has its own specific properties that can be used to identify it.

Mohs hardness scale ranks minerals from soft to hard (1-10).

This is the color that you see when looking at a mineral.

This is the color of the powder. You can only see the color by rubbing it against a scratch plate. This is how a mineral reflects light. It can be shiny, glassy, waxy, pearly, earthy.

How much mass is in a given amount of space. This is what causes objects to sink or float! The shape of the crystal formations are different. These can often be seen by looking at it but sometimes you need a microscope.

How a mineral breaks apart. Minerals can break in chunks, in flat layers, in square pieces, etc. How the mineral looks when it breaks apart.

HARDNESS -

Hardness is the ability of a mineral to resist being scratched. To determine a mineral's hardness, rub the mineral against another known mineral or object to see if it will become scratched. The following chart indicates how you might test a mineral for hardness using a combination of Friedrich Moh's and field hardness scales. 1 represents the softest mineral while 10 is used for the hardest mineral. A mineral is able to scratch a mineral with a lower number and can, therefore be scratched by a mineral with a higher number.

Mohs Hardness Scale

Hardness Item(s) That Will Scratch Mineral Examples

1 Fingernail Talc

2 Fingernail Gypsum

3 Penny Calcite

4 Penny Fluorite

5 Glass, Knife blade, or Nail Apatite

6 Streak Plate Feldspar

7 File Quartz (massive type)Quartz crystal

8 File Topaz

9 File/Diamond Corundum

10 Diamond

DENSITY or SPECIFIC GRAVITY

A mineral's density is the amount of matter in a given space (mass/volume). Each mineral has a characteristic density (density does not vary with the size of the mineral). Specific gravity is the ratio of the density of a mineral compared to the density of water. It is a more specific way to compare the densities of minerals.

COLOR Color is easily observed and the easiest physical property to determine; however, it is not the most useful characteristic in helping to identify a particular mineral. The problem is shown below, in which the mineral fluorite (CaF2) displays a rainbow of colors.

But WHY are minerals different colors?The color of minerals depends on the presence of certain atoms, such as iron or chromium which strongly absorb portions of the light spectrum. The mineral olivine, containing iron, absorbs all colors except green, which it reflects, so we see olivine as green. All natural minerals also contain minute impurities. Some minerals such as corundum get their colors from these impurities. Blue corundum (sapphire) is formed when small amounts of iron and titanium are dissolved in the solid crystal. Finally some crystals get their color from growth imperfections. Smoky (black) quartz is a good example. Growth imperfections interfere with light passing through the crystal making it appear darker, or almost black.

LUSTER A mineral's luster describes the way light is reflected from its surface. Examples of luster include - metallic, nonmetallic, brilliant, glassy, greasy, pearly, or silky.

STREAK The streak of a mineral is the color of the powder left behind when the mineral is rubbed against a hard, rough surface (e.g. streak plate). A mineral's streak color may differ from the color of the mineral itself. This characteristic is most useful for minerals that are relatively soft (have a hardness less than 7) and which have a characteristic streak color.

Mineral Breaks = CLEAVAGE or FRACTURE Cleavage - means to break along a smooth, definite line

Fracture – breakage occurs either on irregular surfaces (splintery or irregular fracture) or along smooth, curved surfaces (conchoidal fracture) (like breaking thick glass)

CRYSTAL SHAPE Crystal shape results from the pattern formed by the mineral’s internal (atomic) structure. Most minerals have a characteristic geometric shape.

Other Properties Magnetism - A few minerals are attracted to a magnet or are themselves capable of acting as magnets (the most common magnetic mineral is magnetite). Because these are so rare, this property helps narrow the possibilities drastically when trying to identify an unknown specimen.

Feel - Some minerals, notably talc and graphite, feel greasy or slippery when you rub your fingers over them. The greasiness occurs because bonds are so weak in one direction that your finger pressure alone is enough to break them and to slide planes of atoms past neighboring atomic layers.

Taste - Geologists use as many senses as possible in describing and identifying minerals. Taste is one of the last tests to be conducted, because some minerals are poisonous. Some minerals taste salty-most notably halite (salt). Sylvite, a mineral similar in all other properties to halite, tastes bitter. Taste is thus a diagnostic property because it distinguishes between these minerals. NEVER TASTE A MINERAL UNLESS INSTRUCTED TO!

Reaction with Dilute Hydrochloric Acid - This is actually a chemical property rather than a physical attribute of a mineral. Minerals containing the carbonate anion (C03)2- effervesce ("fizz") when a drop of dilute hydrochloric acid is placed on them. Carbon dioxide is liberated from the mineral and bubbles out through the acid, creating the fizz. This test is best performed on powdered minerals. Calcite (calcium carbonate) will effervesce readily in either massive or powdered form, but dolomite (calcium-magnesium carbonate) reacts best as a powder.

Answers to EQs:

What is the definition of a mineral?A mineral is a naturally occurring, inorganic solid with a crystalline structure and a definite chemical composition. What is the difference between a rock and a mineral?Rocks are formed from minerals. The combination of minerals that form a rock provides clues as to how the rock was formed.

Why are minerals important resources for our society?Almost everything we use each day is made from minerals

ANSWERS with Minerals:

fluorspar, calcite, barite = toothpastetalc = baby powder

boron, silica = mirrorsfeldspar, silica = glass kaolin = newspapergraphite = tennis racketcopper = electrical cord, wirewollastonite, mica = penmica = carpumice = pencil erasers, cleansersbauxite = soda canclay = potterylimestone, bauxite, clay, shale, and gypsum = cement