Topic 11

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It is a:  naturally occurring substance  inorganic,  solid,  has a definite chemical composition  has a crystal structure. Page 2 A. What is a mineral?

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1. A mineral occurs naturally. It is not man-made a.Minerals – quartz, and pyrite b.Not minerals – cement, and steel Page 2

2. A mineral is inorganic because it was never alive a. ______ is not a mineral because it comes from________. is not a mineral because it comes from_________. b.________ c.________ coal plants amber tree sap pearl oysters Page 2

3. A mineral has a definite chemical composition. It has a chemical symbol or formula Glass is not a mineral because it does not have a chemical symbol or formula Page 2

4. A mineral is solid. Solids – have a definite _______________ and a definite __________. Oil is not a mineral because it is a _________. liquid size/volume shape Page 2

5. A mineral’s atoms are arranged in an orderly pattern. (Crystal Structure) Atoms are arranged in repeating patterns a.k.a. internal structure. Each mineral has a unique pattern It determines how strong or weak the mineral is Page 2

5. A mineral’s atoms are arranged in an orderly pattern. (Crystal Structure) Page 2

B. What causes minerals to have different physical properties? their internal arrangement of atoms Page 2

Give an example of two minerals which have the same chemical composition but different physical properties Page 2

Internal arrangement of atoms determines a minerals properties (cleavage, hardness, luster, etc) Page 2

Diamond vs Graphite- Both made of the same element, but formed in different environments. Page 2

To be able to identify these minerals, we need to look at the properties used to separate and distinguish these minerals. Page 2

Remember: Rarely is a mineral identified by a single property. Several properties need to be considered together to correctly identify a mineral. Mineral can be identified by their physical and chemical properties Page 2

Minerals are Found in the Earth Science Reference Tables (ESRT) page 16 Hi my name is Chaz. Check out the ESRT! Page 2

C. The Main Physical Properties Used to Identify Minerals 1. Color a poor indicator because: a. A certain mineral can be multiple or many colors b. many minerals are the same color c. Color can change over time due to exposure Page 2

Color is the most easily observed mineral property and the least useful! a. Some minerals have only one color: 1. Malachite - green 2. Sulfur - yellow b. Other minerals have many colors: 1. Quartz - clear, pink, purple, white, smoky 2. Hematite – black, grey, reddish brown Page 2 Show hand samples

Color is the most easily observed mineral property and the least useful! b. Other minerals have many colors: Page 2

b. Many minerals have a similar color. Page 2

C. Color can vary as the result of impurities, or change over time for various circumstances. Page 2

For example, pure quartz is colorless or white, impurities can make the mineral rose, purple or pink! Page 2

How many of the characteristics of minerals can you name? Why isn’t color a very good property to identify most minerals? Page 2

Streak: Page 2 is the color of the mineral in powdered form

a. How to test for streak: Page 2 Rub the mineral on an unglazed white or black ceramic tile b. more reliable than color

Hematite – colors- dark red reddish brown grey black Streak will always be reddish- brown Quartz – colors – colorless to variety of colors Streak will always be white/colorless Page 2 =

Luster the way a mineral shines in reflected light Page 2

The mineral on the left has a metallic luster, the one on the right, a nonmetallic luster Page 2

C. The Main Physical Properties Used to Identify Minerals 3. Luster how light reflects off a mineral a. metallicb. non-metallic looks like a Metal & feels like a metal b/c it heavy for its size looks dirty, earthy, waxy, greasy Page 2

There are several terms used to describe nonmetallic luster. Examples could be vitreous, like the quartz on the left, or pearly, like the gypsum on the right. Page 2

The Main Physical Properties Used to Identify Minerals Luster how light reflects off a mineral metallicnon-metallic looks like a metal looks earthy, waxy, greasy Page 2

Luster - the way a mineral shines Metallic- looks like metal Page 2

Non-metallic : does not look like metal Page 2

Vitreous - looks like glass, most common type of non- metallic luster Page 2

Dull/earthy - no shine, looks like dirt Page 2

Resinous - looks waxy Page 2

Other terms that might be used include greasy, dull, and earthy. Can you tell which of these has an earthy luster and which has a vitreous luster? Earthy Vitreous Page 2

4. Breakage C. The Main Physical Properties Used to Identify Minerals How a mineral breaks apart Page 3

C. The Main Physical Properties Used to Identify Minerals a. Cleavage: The mineral breaks in a predictable pattern. It is a clean break which leaves smooth sides. C. What determines how the mineral breaks? Internal arrangement of the atoms. b. Fracture: the mineral breaks randomly Page 3

Mica is probably the best example as it splits into thin sheets. It is said to have one perfect cleavage. Page 3

Feldspar splits readily in two directions, always at or near right angles. Page 3

Calcite and galena cleave in three directions. They are said to have three good cleavages. Page 3

Not all minerals show cleavage. Those that don’t break along cleavage surfaces are said to have fracture. Page 3

When a mineral breaks unevenly into rough jagged surfaces Examples of minerals that show fracture are SULFUR & QUARTZ Page 3

5. Hardness C. The Main Physical Properties Used to Identify Minerals resistance to being scratched a. How to test: scratch mineral on glass b. What determines mineral’s hardness? Page 3

Key Concept #3 Hardness The Main Physical Properties Used to Identify Minerals c. MOH’S SCALE OF HARDNESS Page 3

The hardness of a mineral is its resistance to being scratched. Diamond is the hardest of all minerals, and talc is the softest. Page 3

The hardness of a mineral is its resistance to being scratched. Diamond is the hardest of all minerals, and talc is the softest. Page 3

Friedrich Mohs devised a hardness scale. In this scale, ten wellknown minerals are given numbers from one to ten. Lets take a look at the ten minerals used and some of the simple tests. Page 3

Talc (left) is the softest and has a hardness of 1. A soft pencil lead will scratch talc. Gypsum is a bit harder and has a hardness of 2. A fingernail scratches gypsum. Page 3

Calcite (left) has a hardness of 3 and a copper penny just scratches it. Fluorite has a hardness of 4 and it can be scratched by an iron or brass nail. Page 3

Apatite (left) has a hardness of 5 and can be scratched by a steel knife blade. Feldspar has a hardness of 6 and it will scratch a window glass. Page 3

Quartz (left), with a hardness of 7, is the hardest of the common minerals. It easily scratches hard glass and steel. Topaz has a hardness of 8 and will scratch quartz. Page 3

Corundum (left) has a hardness of 9. Corundum will scratch topaz. Diamond with its hardness of 10 can easily scratch the rest of the minerals. Page 3

What determines Hardness? THE MINERALS INTERNAL ARRANGEMENT OF ATOMS OR MOLECULAR STRUCTURE Page 3

Does this mineral show cleavage or fracture? Which mineral has the highest hardness? Page 3

Specific gravity tells you how many times as dense as water the mineral is. Pure gold can have a specific gravity as high as 19.3! A piece of gold has 8 times as much mass as a piece of halite that is the same size. Did you know a 11.2 centimeter cube of gold would weigh 2000 lbs. WOW, That’s heavy dude!!! Page 3

Calcite is calcium carbonate, CaCO 3. If a drop of weak hydrochloric acid is placed on calcite, the acid bubbles as carbon dioxide is released. 6. Other Miscellaneous Properties: Page 3

Some minerals that contain Iron, are magnetic and can be picked up by a magnet. Lodestone, a form of the mineral magnetite, is naturally magnetic. 6. Other Miscellaneous Properties: Page 3

Halite (rock salt) can be identified by its taste. This practice is not recommended! Page 3

This is the state of glowing while under an ultraviolet light. Some minerals even glow once the light is turned off! Page 3

Fluorescence - some minerals glow when exposed to UV light Page 3

Iceland spar, a form of the mineral calcite, produces double refraction Page 3

Malleable Magnetic Radioactive Flourescence Taste Page 3

Some minerals, such as this uraninite, are radioactive. They give off subatomic particles that will activate a Geiger counter. Page 3

Sulfur Odor- smells like rotten eggs- scratch & sniff Page 3

Based on the chemical composition or elemental make-up Page 3

___________- most common group of minerals. Contain Si (silicon) and O (oxygen) the 2 most abundant elements in Earth’s crust. Silicates makes up 90% of all minerals. Silicates Page 4

Carbonates- commonly found in sedimentary rocks. All contain carbonate (CO 3 ). Most important carbonate mineral is calcite. Page 4

Iron Oxides & Sulfides- Oxides consist of metal combined with oxygen. Sulfides consist of metal with sulfur. Page 4

Other families- provide a number of nonmetallic resources, which are phosphates, halides and sulfates. We get salt, fertilizer, sulfuric acid, plaster from these minerals. Gypsum- plaster Sulfuric acid & fertilizers Page 4

Native- these minerals are very rare. Most minerals are made of more than one element, only a few can be found in Earth’s crust as pure elements. Page 4

Minerals have a definite chemical composition. D. What two elements, by mass, make up the greatest percentage of the Earth’s crust? b. silicona. oxygen Page 4

Key Concept #4 Minerals have a definite chemical composition. These two elements combine to form compounds called silicates (SiO 4 ) Page 4

Key Concept #4 Minerals have a definite chemical composition. They combine in a specific structure called a: silicon-oxygen tetrahedra Page 4

INTERNAL ARRANGEMENT OF THE ATOMS how the atoms are arranged in it. This arrangement of atoms is called a tetrahedron. It has four sides. It is made up of one silicon (red), surrounded by four oxygen atoms (brown, there is one hidden on the other side) **Draw diagram in your note packet on page 2** Page 4

REGENTS QUESTIONS ABOUT SILICON- OXYGEN TETRAHEDRONS Can you answer them? Page 4

Answers to questions Page 4 1. Nitrogen 2. Hydrogen % 4. 21% Potassium 7. Magnesium 8. Oxygen

Minerals are Found in the Earth Science Reference Tables (ESRT) page 16 Hi my name is Chaz. Check out the ESRT! Page 4

Answers to questions Page 5 1. Naturally occurring, inorganic, solid, have a definite chemical composition, & crystalline structure 2. Internal arrangement of atoms or molecular structure 3. Many minerals have the same color or the a mineral could be many different colors 4. Mineral looks like a metal (usually heavy for its size) 5. Silicon & Oxygen 6. Garnet 7. Graphite

Answers to questions Page 5 8. Mg 3 Si 4 O 10 (OH) 2 9. Fracture 10. Calcite will bubble with acid & Halite tastes salty 11. Olivine 12. Potassium Feldspar 13. Quartz 14. Fluorite 15. Silicon & Oxygen

Answers to questions Page Streak test performed by rubbing the mineral on a ceramic tile 17. Hardness 18. Calcite 19. Talc 20. Graphite 21. Magnesium

Answers to questions Page 6 1. a 2. a 3. d 4. a 5. d 6. c 7. c 8. a 9. b 10. b 11. a 12. b 13. d