Earth Materials SCRATCH TEST Lori Mitchell
We are the Rock Hounds Been looking for clues Time after time Hounded volcanoes Searching the old mines Found plenty of rocks And minerals too I’ve found my share of rocks and granite And I’ve sifted through
We are the rock hounds – my friends And we’ll keep on searching – till the end We are the rock hounds No time for snoozers Cause we are the rock hounds Of the world
OBSERVING MINERALS Each Group needs: a FOSS tray two hand lenses 4 sticky notes 4 Page 8 of Earth Materials Booklet 4 Student sheets “Mineral Properties”
Mineral Properties Each student will practice identifying simple properties and how to handle two properties at one time by filling out the Mineral Properties sheet. Discuss results
Observing Properties Number the sticky notes 1-4 and place them in the compartments of the FOSS tray. Student 1 will pick up mineral 1 and place it in the group tray compartment labeled number 1. Students 2 will pick up mineral 2, and so on.
Observing Properties Observe the minerals carefully using your hand lens. (Be careful not to mix them up) Record your observations on page 8 Remember to write observations so detailed you would be able to identify each mineral from your notes, if the numbers were taken away.
SHARING OBSERVATIONS Share observations with the class. Can we identify your mineral from your notes? Which of the properties is most useful in helping you identify a certain mineral? Is one property enough information to identify a mineral? What if I gave you the clue “It’s a small mineral.” Would that be enough information to identify any sample of that mineral? Do you think you could identify each mineral on another group’s tray if you didn’t have the numbers to help?
Wrapping it Up What is a mineral? What is the difference between a rock and a mineral? If someone sent you a letter and said they needed your help to identify a mineral that they had found, and they told you it was about the size of your fist would you be able to identify it?
Mineral #1
Mineral #2
Mineral #3
Mineral # 4
Scratch Test Gather materials: Tray containing the 4 minerals, hand lenses, pennies, paper clip, chalk, tile
CLUE: Quartz is white HOLD UP QUARTZ
Scratch Test Try to scratch a piece of chalk and the tile with the paper clip Use your finger to rub away any dust or surface marks Use a hand lens to check for a scratch Test the tile and the chalk. Which tool is harder, the paper clip or the penny.
CLUE #2 I read that quartz is the hardest of the common minerals on earth. Will that information help you identify the quartz sample in your set? You might want to start with the hardest tool.
Looking For Gypsum Clue: It is the softest of the 4 minerals. Use your scratch tools to identify it.
Record Information You will need page 9 of your Earth Materials booklet. Write in Quartz for #2 Write in Gypsum for # 3 Fill in the appropriate information
Mineral Tool How many tools could Scratch this mineral? Paper clip Penny Fingernail 1 2Quartz No 0 3Gypsum yes 3 4
Calcite and Fluorite CLUE: Fluorite is harder than Calcite What do you already know about these minerals from the tests you have already done? Which scratch tool might give you the best information at this time? How could you find out which was harder if you didn’t have any scratch tools?
Mineral Tool How many tools could Scratch this mineral? Paper clip Penny Fingernail 1. Calcite Yes No2 2Quartz No 0 3Gypsum yes 3 4. Fluorite YesNo 1
ORDER OF HARDNESS Gypsum Calcite Fluorite Quartz Ordered from softest to hardest
FOLLOW UP What do we mean when we say a mineral has a certain hardness? If you didn’t have any tools, how could you learn if one mineral was harder than another?
CALCITE A common mineral & chemical composition is calcium carbonate. It can be scratched with a penny
QUARTZ one of most common minerals and is made up of silicon and oxygen
GYPSUM A mineral that forms when seawater evaporates under arid conditions
FLUORITE Is found in a variety of colors-white, green, blue, & violet. It can be scratched with a gym clip.
Mohs’ Numerical Mineral Scale Talc is the softest mineral-1 Diamond is the hardest mineral - 10
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