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ROCKS AND MINERALS. WOW. . . HOW EXCITING! ROCK ON!. BELIEVE IT OR NOT, EVERY ROCK HAS A STORY TO TELL . . . MAYBE IT :. FORMED DEEP INSIDE THE EARTH A BILLION YEARS AGO FORMED FROM A VOLCANO WAS PART OF AN ANCIENT TROPICAL OCEAN HAS FOSSILS FROM A PREHISTORIC ERA
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ROCKS AND MINERALS WOW. . . HOW EXCITING! ROCK ON!
BELIEVE IT OR NOT, EVERY ROCK HAS A STORY TO TELL . . . MAYBE IT : • FORMED DEEP INSIDE THE EARTH A BILLION YEARS AGO • FORMED FROM A VOLCANO • WAS PART OF AN ANCIENT TROPICAL OCEAN • HAS FOSSILS FROM A PREHISTORIC ERA • WAS MOVED BY A GLACIER, RIVERS AND OCEAN!
ROCKS ARE MADE OF MINERALS… . . SO WHAT ARE MINERALS? • NATURALLY OCCURING • SOLID • INORGANIC • HAVE A UNIQUE CHEMICAL AND MOLECULAR STRUCTURE • MAY FORM CRYSTALS
COLOR STREAK LUSTER HARDNESS FRACTURE OR CLEAVAGE MAGNETIC REACTS WITH ACID LIGHT REFRACTION TASTE MINERALS ARE IDENTIFIED BY PHYSICAL “TESTS”
ALL MINERAL CHARACTERISTICS ARE DETERMINED BY . . . • “THE INTERNAL ARRANGEMENT OF THE ATOMS” • COLOR • STREAK • HARDNESS • LUSTER • FRACTURE OR CLEAVAGE
COLOR • VERY VISIBLE, BUT UNRELIABLE: • MANY MINERALS HAVE THE SAME COLOR • MANY MINERALS COME IN A VARIETY OF COLORS
STREAK • THE COLOR OF A MINERAL IN ITS POWDERED FORM • THE POWDER MAY BE A DIFFERENT COLOR THAN THE MINERAL • USE A “STREAK PLATE” TO TEST
LUSTER • THE WAY LIGHT IS REFLECTED FROM THE MINERAL: • METALLIC WHICH SHINES LIKE POLISHED METALS • NONMETALLIC SO IT MAY BE GLOSSY, DULL, WAXY
HARDNESS • THE RESISTANCE TO BEING SCRATCHED • WE TEST HARDNESS BY SEEING IF THE MINERAL CAN SCRATCH GLASS • MOH’S SCALE 1-10 • TALC IS 1 AND • DIAMOND IS 10
BY THE WAY, WHO IS MOH? • OH. . . FREIDRICH MOH, A GEOLOGIST FROM THE 1800’S!
WHY WOULD WE CARE ABOUT MINERAL HARDNESS? • IT AFFECTS HOW HARD OR SOFT ROCKS ARE • THE DURABILITY OF MONUMNENTS AND BUILDINGS
FRACTURE OR CLEAVAGE • HOW A MINERAL SPECIMEN BREAKS • JAGGED AND UNVEN IS FRACTURE • BREAKING ON A SMOOTH SURFACE OR “PLANE” IS CLEAVAGE
AND WHAT CAUSES THIS CHARACTERISTIC? • THE INTERNAL ARRANGEMENT OF THE ATOMS! • THE INTERNAL ARRANGEMENT OF THE ATOMS!
THE OTHER TESTS. . . • LIGHT REFRACTION • MAGNETIC • REACTS WITH ACID
SO, WHAT ARE THE TESTS TO IDENTIFY MINERALS? • COLOR • STREAK • LUSTER • HARDNESS • FRACTURE AND CLEAVAGE
WHY SHOULD WE CARE ABOUT MINERALS? • MINERALS MAKE UP ROCKS, AND EVERY ROCK HAS A STORY TO TELL! • MINERALS PROVIDE LOTS OF RAW MATERIALS FOR MANY THINGS WE USE