MINERALS! 2015 Ms. Broys Class ROCKS ARE MADE UP OF ONE OR MORE MINERALS! WHAT IS A MINERAL? Naturally occurring (comes from nature, not a laboratory) A solid (well unless it finds itself inside the earth in the mantle!) Inorganic (was never a living thing) Has a fixed chemical formula Has an ordered crystal structure PROPERTIES OF MINERALS Streak color of the powder left behind Luster way the mineral surface reflects light Hardness the mineralss ability to resist being scratched (Tested according to Mohs Hardness Scale) Color Mohs Hardness Scale Used to measure a minerals ability to resist being scratched. What is the hardest mineral? What is the softest? Which mineral(s) could leave a scratch on fluorite? MOHS HARDNESS SCALE Scratching tools: fingernail (2.2) copper penny (3.5) pocket knife or common nail (5.2) piece of glass (5.5) steel file or concrete nail (7.5) piece of corundum (9) Each mineral can scratch the minerals with lower hardness ratings. Each mineral can scratch itself.