Mineral or Nonmineral? YES YES YES YES YES Definite chemical composition MINERAL NON-MINERAL NON-MINERAL MINERAL NON-MINERAL Mineral or nonmineral YES NO YES YES NO Crystal Structure YES NO YES YES YES Solid YES NO NO YES YES Inorganic YES YES YES YES NO Naturally occurring diamond water coal quartz rubber ball mineral characteristics
What is a mineral ? naturally occurring solid crystal structure inorganic definite chemical composition
mineral splits easily along flat surfaces cleavage mass/volume density fluorescence, magnetism, radioactive, react to acid, electrical properties special properties how mineral looks when it breaks apart fracture crystal shape how mineral reflects light on its surface luster color of mineral’s powder on streak plate streak color use Mohs hardness scale hardness
MOH’S SCALE OF HARDNESS <ul><li>1. Talc 6. Feldspar </li></ul><ul><li>2. Gypsum 7. Quartz </li></ul><ul><li>3. Calcite 8. Topaz </li></ul><ul><li>4. Fluorite 9. Corundum </li></ul><ul><li>5. Apatite 10. </li></ul>scale that ranks minerals from softest to hardest: the higher the number, the harder the mineral
Mohs Hardness Scale #1 Talc #2 Gypsum #3 Calcite #4 Fluorite #5 Apatite #6 Feldspar #7 Quartz #8 Topaz #9 Corundum #10 Diamond To remember the Mohs scale try remembering this phrase: T he G eologist C an F ind A F antastic Q uartz, T ourists C all D iamond!
Tools for Testing Hardness <ul><li>You typically do not carry around a supply of the 10 minerals on the hardness scale. However, you can use the following items to help estimate the hardness of a mineral: </li></ul>Finger Nail (H = 2.5) Penny (H = 3) Knife Blade (H = 5.5)
Quartz ranks a 7 on Mohs hardness scale. It can scratch steel and hard glass easily.
<ul><li>C o l o r is an excellent way to compare minerals—it's one of the first things that a geologist looks at. </li></ul><ul><li>Minerals come in many colors—and colors are one reason that minerals are so appealing! </li></ul><ul><li>Many minerals are known for their beautiful color. </li></ul>
Luster Tourmanline has a vitreous (glassy) luster. Gold has a metallic luster. Talc has a pearly luster. Metallic Glassy Waxy Greasy Pearly Dull Silky Earthy
<ul><li>Metallic - opaque and reflective, like metal. </li></ul><ul><li>Submetallic - opaque to nearly opaque and reflect well. Thin splinters or sections of submetallic minerals are translucent. </li></ul><ul><li>Vitreous - reflective properties similar to glass. </li></ul><ul><li>Adamantine - Transparent to translucent minerals with a high refractive index -display extraordinary brilliance and shine. </li></ul><ul><li>Resinous - yellow, dark orange, or brown minerals -honey like, but not necessarily the same color. </li></ul><ul><li>Silky - have optical properties similar to silk cloth. </li></ul><ul><li>Pearly - Describes a luster similar to the inside of a mollusk shell or shirt button. </li></ul><ul><li>Greasy - Luster of a mineral that appears as if it were coated with grease. </li></ul><ul><li>Pitchy - tar-like appearence have a pitchy luster. </li></ul><ul><li>Waxy - appears as if it were coated with a layer wax. </li></ul><ul><li>Dull - poor reflective qualities, much like unglazed porcelain. have a rough or porous surface. </li></ul>
Density Mica has a very low density— just 2.8 Galena's density is 7.5 Gold has one of the highest densities—19.3! Some minerals are denser than others. That means they weigh more than other minerals of the same size. Why? Because the atoms inside are heavier or packed more tightly together. Density is also called 'specific gravity.'
<ul><li>Pyrite is called fool's gold because its brassy yellow color is very similar to gold . </li></ul><ul><li>Although it looks like gold, its other physical properties are very different. </li></ul><ul><li>Pyrite is harder, less dense, and more brittle. It leaves a greenish-black streak while gold leaves a golden-yellow one. </li></ul>
Radioactivity <ul><li>To look at radioactive minerals, you cannot see the energy being released and the damage that these minerals can cause to living organisms often until it’s too late. </li></ul><ul><li>This energy can however be detected with a Geiger Counter which will show it. </li></ul>Geiger Counter
Grow Your Own Crystals <ul><li>To make your own salt crystals, you'll need a few items from around the house. A heat-proof, glass jar (a mason jar is excellent.) A measuring cup About 1 cup of boiling water About 1/2 cup of salt A pencil Cotton string A spoon A paperclip A paper towel </li></ul>
Prepare a Supersaturated Solution <ul><li>Tie the paper clip to one end of the string, and the pencil to the other end. When you place the pencil across the top of the jar, the string should be just long enough to let the paper clip touch the bottom. Set the string, pencil, and paper clip aside. </li></ul><ul><li>Boil about 1 cup of water, either in the microwave or on the stove. Pour the boiling water into the jar. Add the salt one teaspoonful at a time. Stir until each teaspoon is completely dissolved. You may be tempted to add all the salt at once, but the experiment won't work as well if you do. Be patient. Eventually, you'll find a small amount of salt will not dissolve and collects at the bottom of the jar. You have reached supersaturation. Once the solution is supersaturated, stop adding salt. </li></ul><ul><li>Next, you'll put it all together -- and find out what to do with that string and the paper towel. </li></ul>
Put It All Together <ul><li>Lower the paper clip and string into the water and rest the pencil across the top of the jar. Cover the jar lightly with a paper towel. This will keep dust out of the jar. Place the jar where it won't be disturbed for a couple of days. </li></ul><ul><li>Table salt (halite) crystals form as cubes. After about 12 hours, you should be able to see small crystals forming at the bottom of the jar, on the paper clip, and along the string. Some may even form on the surface of the water, like a wreath around the string. After 24 hours, you should see definite crystal forms. </li></ul><ul><li>After all this work, let's see the results and how to find out more about minerals. </li></ul>
Results and Resources <ul><li>After one or two days, you'll be able to see cubes of salt crystals. Some may form alone and grow larger, while others may form clusters. </li></ul><ul><li>If you'd like to experiment with another mineral that has a completely different shape, try using 1 and 1/2 cups of Epsom salts (magnesium sulfate) instead of 1/2 cup of salt. The Epsom salt crystals will tend to form on the bottom of the jar and are generally shaped like stubby prisms. </li></ul>
Properties of minerals Name of Mineral Color of mineral Luster Color of streak
Activity- Finding the Density of Minerals Snowflake Obsidian Malachite Density (g/cm 3 ) Volume of water displaced (cm 3 ) Volume of water displaced (mL) Volume of water with mineral (mL) Volume of water without mineral (mL) Mass of mineral (g) Hematite Citrine Amethyst
Activity- Finding the Density of Minerals 5.17 g/cm 3 2.67 g/cm 3 3 g/cm 3 Density (g/cm 3 ) 29 cm 3 30 cm 3 5 cm 3 Volume of water displaced (cm 3 ) 29 mL 30 mL 5 mL Volume of water displaced (mL) 129 mL 130 mL 105 mL Volume of water with mineral (mL) 100 mL 100 mL 100 mL Volume of water without mineral (mL) 150 g 80 g 15 g Mass of mineral (g) Hematite Quartz Pyrite
A Mouthful of Minerals Problem: What effect do the minerals in toothpaste have on the toothpaste’s ability to clean? Ultra-Brite Gleem Colgate Observations Predictions Minerals Present Toothpaste
A Mouthful of Minerals Problem: What effect do the minerals in toothpaste have on the toothpaste’s ability to clean? Sodium flouride, silica, tetrasodium pyrophosphate, titanium dioxide Ultra-Brite Sodium flouride, silica, titanium dioxide, sodium phosphate Gleem Silica, sodium bicarbonate, sodium flouride, calcium, titanium dioxide Colgate Observations Predictions Minerals Present Toothpaste