WHAT IS A MINERAL?-NATURALLY OCCURING, INORGANIC SUBSTANCES

MINERALS ARE THE BUILDING BLOCKS OF ROCKS. YOU CAN’T HAVE A ROCK WITHOUT MINERALS

- THOUSANDS OF MINERALS HAVE BEEN IDENTIFIED, BUT ONLY ABOUT A DOZEN ARE COMMONLY FOUND

GRAPHITE AND DIAMOND ARE DIFFERENT FORMS OF THE ELEMENT CARBON

- SOME ARE CHEMICAL ELEMENTS OR COMPOUNDS

- SILICON AND OXYGEN ARE THE TWO MOST COMMON ELEMENTS IN THE EARTH’S CRUST

WAYS TO IDENTIFY A PARTICULAR MINERAL!

-MANY MINERALS HAVE A CHARACTERISTIC COLOR

EX: PYRITE “FOOLS GOLD” IS TYPICALLY A BRASSY YELLOW COLOR

-UNFORTUNTAELY, MANY CLEAR OR WHITE MINERALS ARE A VARIETY OF DIFFERENT COLORS BECAUSE OF IMPURITES… COLOR IS NOT A GOOD IDENTIFIER!

1) METALLIC LUSTER: LOOK, LIKE POLISHED METAL. LIGHT CANNOT GET THROUGH

EX: GALENA, PYRITE

- THE WAY LIGHT IS REFLECTED OFF A FRESHLY CUT SURFACE.. 2 TYPES

2) NON-METALLIC LUSTER: CAN BE SHINY, BUT DO NOT LOOK LIKE METAL.

EX: QUARTZ, SULFUR

- THE MINERAL IN POWDERED FORM

TESTING FOR STREAK:

RUB FRESH EDGE OF MINERAL ACROSS A WHITE, UNGLAZED TILE.

** SOME MINERALS LEAVE A POWDER THAT IS NOT THE SAME COLOR AS THE MINERAL

EX: PYRITE

-THE ABILITY OF A MINERAL TO SCRATCH OTHER SOLID OBJECTS

-OBJECTS THAT WE WILL SCRATCH IN ORDER TO TEST FOR HARDNESS INCLUDE….

-YOUR FINGERNAIL (SOFTEST)

-A PENNY

-A GLASS PLATE (HARDEST)

MOH’S HARDNESS SCALE:

-THIS SCALE ASSIGNS MINERALS A HARDNESS NUMBER

- IF THE MINERAL IS A “1” ON THIS SCALE, IT IS CONSIDERED TO BE ONE OF THE SOFTEST MINERALS

-IF A MINERAL IS A “10” ON THIS SCALE, IT IS CONSIDERED TO BE ONE OF THE HARDEST MINERALS

SOME MINERALS BREAK UPON FLAT SURFACES CALLED, CLEAVAGE PLANES

EX: HALITE: BREAKS INTO CUBES

BIOTITE AND MUSCOVITE: BREAK INTO SHEETS

FRACTURE: WHEN A MINERAL DOES NOT BREAK ON AN EVEN CLEAVAGE PLANE.

EX: QUARTZ( CONCHOIDAL FRACTURE)

HALITE

MICA

POTASSIUM FELDSPAR

CALCITE

QUARTZ

OLIVINE

GARNET

CRYSTAL: REGULARLY SHAPED SOLID FORMED BY AN ORDERED PATTERN OF ATOMS- MINERALS FORM CHARACTERISTICALLY SHAPED CRYSTALSEX: CALCITE AND HALITE LOOK VERY SIMILAR.

CALCITE= SQUISHED BOX CRYSTALS

HALITE= REGULAR BOX CRYSTALS

HALITE

CALCITE

DOES IT FEEL HEAVY FOR IT’S SIZE?

EX: GALENA= VERY DENSE