MINERAL-HARDNESS. 230 Investigation 2: Scratch Test

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1 Date MINERAL HARDNESS MINERAL-HARDNESS TEST PROCEDURE 1. Start with your fingernail. 2. Try to scratch all four minerals with your fingernail. 3. If your fingernail scratches the mineral, write "yes" in the chart. 4. If your fingernail does not scratch the mineral, write "no" in the chart. 5. Follow the same procedure with the aluminum nail and then with the steel paper clip. MINERAL TOOL 1, Fln~mail Aluminum Steel (paper (nail) clip) How many tools could scratch this minerai? 2 3, 4 List the four minerals from hardest to softest. Hardness information: Quartz is hardest. Gypsum is softest. Fluorite is harder than calcite. FOSS Solid Earth The Regents of the UniVeesity of Cafifcnja Can be duplicated for classroom or workshop I!ISe. 230 Investigation 2: Scratch Test Nb. 8-Scfeooe, Notebook

2 MINERAL HARDNESS MINERAL-HARDNESS TEST PROCEDURE 1. Start with your fingernail. 2. Try to scratch all four minerals with your fingernail. 3. If your fingernail scratches the mineral, write "yes" in the chart. 4. If your fingernail does not scratch the mineral, write "no" in the chart. 5. Follow the same procedure with the aluminum nail and then with the steel paper clip. DATA TOOL - Co) c 'tj :; 'i,e- ll) c ftj U '0 'E e II) - 'cu E a. >- :E cu e e - ~ a. cu c.c: - E (J 'E... Gi." ;: -cu c ~... 0 Co) Mineral i:i: Ci 0 :z:: II) 1 calcite no yes yes 2 2 quartz no no no 0 3 gypsum yes yes yes 3 4f1. iuori+e no no yes 1 LIST THE FOUR MINERALS HARDEST TO SOFTEST. FROM quartz fluorite calcite gypsum

3 ES4b. Students know how to identify common rock-forming minerals (including quartz, calcite, feldspar, mica, and hornblende) and ore minerals by using a table of diagnostic,l)roperties. eologists use a number Mohs hardness scale scale to describe mineral hardness. Friedrich Mohs 10 Vialftot1d ( ) came up with the scale. Mohs was a German scientist who studied.minerals. He knew that, 9 Corut1dulft some minerals could scratch others. ~ If one mineral could scratch I another, it must be harder than the 8 ropaz mineral that was scratched. The Mohs hardness scale goes from 1 (soft) to 10 (hard). The.meral talc, the softest mineral, has a hardness of 1. Diamond, the hardest mineral, has a hardness of 10. All the other minerals fall between talc and diamond. These ten minerals represent the ten levels of hardness. 7 Quartz 6 Feldspar 5 Apatite Between the hardest and softest minerals are all the other minerals. 4 Fluorite Minerals with higher numbers on the Mohs scale will scratch minerals with lower numbers. Calcite 3 Calcite can scratch gypsum, but it cannot scratch fluorite. Quartz can scratch feldspar, but it cannot 2 Gypsulft scratch topaz. 1 rale 195 I II

4 The minerals at the hard end of the Mohs scale are called gems. Gems are hard minerals that can be cut into beau. -, shapes. Because they ate hard, they last a very long time. People have identified gem minerals with the months of tk ~ These gems are called birthstones. At one time, people ~ birthstones could protect, heal, or bring good luck. Some birthstones were thought to have magical powers. Which of beautiful minerals is your birthstone? January: &arnet Often colored red, garnet crystals form easil: rock. Long ago, people believed a garnet wo protect its owner from wounds. February: Amethyst Amethyst is a form of quartz that is purple. Amethysts were once thought to keep soldiers s in battle. March: Aquamarine The mineral beryl forms crystals of different colors. Blue crystals are called aquamarines. Aquamarines were supposed to bring good lu to sailors at sea. II: "". er- " ' :.,::".1-:, ~ ~-:: April: Oiamon~ It takes extreme heat and pressure to turn carbon into diamond. Diamond is the harde: natural substance in the world. Some people believed a diamond would give them strength May: Emerald Unlike other gems, emeralds are not found washed into streams. They must be mined fr other rock. It was said that an emerald place under the tongue lets you see the future. June: Alexandrite Along with pearl, alexandrite is the birthstom for June. This mineral is both rare and uniqui In natural sunlight it looks green. But whee i lit by a lightbulb, it looks red.

5 July: Ruby Most rubies are found in streambeds or under soil. It was thought that a ruby turning dark warned its owner of danger. August: Peridot Green and yellow-green peri dots are forms of the mineral olivine. They can be found in lava flows and in meteorites. Peridot is the only gem that may come from outer space! Peridot was said to give its wearer dignity. I September: Sapphire Both sapphires (blue) and rubies (red) are crystals of the same mineral, corundum. Legend says a sapphire will make a foolish person WIse. lctober: Opal Opals can be clear, cloudy, or opaque. Opals of good quality may show rainbowlike colors. The Romans wore opals for love and hope. November: Topaz Pure topaz is colorless. Impurities can make topaz yellow, blue, green, orange, or pink. In the Middle Ages, topaz was said to improve the mind. The largest known topaz crystal weighs 271 kilograms (596 pounds)! Oecember: Turquoise Bluish gre-en turquoise is an opaque mineral that is rarely found in crystal form. Native Americans of the Navajo tribe believed a turquoise thrown into a river with a prayer would bring rain.

6 ) J Name: _ Date: _ Minerals/(jemstones What I wonder before I read... What I wonder as I read... What I am confused about...