MINERALS

MINERALS ARE MADE UP OF SINGLE ELEMENTS OR COMPOUNDS A SUBSTANCE THAT CANNOT BE BROKEN DOWN TO ANY SIMPLER SUBSTANCE EIGHT MOST COMMON ELEMENTS IN THE EARTH’S CRUST: 1.) OXYGEN 46% 3-8.)THE REMAINING 25% IS COMPOSED OF Al, Fe, Ca, Na, K, Mg 2.) SILICON 29%

A MINERAL IS: 1.) NATURALLY OCCURRING 2.) DEFINITE CHEMICAL COMPOSITION 3.) INORGANIC SOLID 4.) CRYSTALLINE STRUCTURE 5.) DEFINITE SET OF CHEMICAL AND PHYSICAL PROPERTIES

FAMILIES OF MINERALS Native Minerals ARE COMPOSED OF SINGLE ELEMENTS. Au (aurum) GOLD Ag (argentium) SILVER Cu (cuprum) COPPER S SULFUR C GRAPHITE OR DIAMOND

HALITE (NaCl) QUARTZ (SiO2) MOST MINERALS ARE COMPOSED OF TWO OR MORE ELEMENTS HALITE (NaCl) QUARTZ (SiO2)

SILICATES • OXYGEN AND SILICON COMBINE READILY WITH EACH OTHER AND WITH OTHER ELEMENTS TO FORM THIS FAMILY OF MINERALS • MOST COMMON FAMILY OF MINERALS AND MAKE UP OVER 90% OF ALL MINERALS • THIS IS BECAUSE OXYGEN AND SILICON ARE THE MOST COMMON ELEMENTS IN THE EARTH’S CRUST

NOW CIRCLE ALL OF THE MINERALS ON YOUR NOTESHEET WHICH ARE SILICATES * ANY MINERAL WHICH IS A SILICATE MUST CONTAIN Si (SILICON) AND O (OXYGEN) IN THEIR CHEMICAL FORMULA NOW CIRCLE ALL OF THE MINERALS ON YOUR NOTESHEET WHICH ARE SILICATES ORTHOCLASE AUGITE QUARTZ OLIVINE BIOTITE

PHYSICAL PROPERTIES THE PHYSICAL PROPERTIES OF MINERALS ARE A REFLECTIONOF THE INTERNAL ARRANGEMENT OF THEIR ATOMS

COLOR LEAST USEFUL PROPERTY, CHANGE IN THE CHEMICAL FORMULA WILL VARY THE COLOR OF THE MINERAL. (QUARTZ) SiO2 ROSE QUARTZ CONTAINS TITANIUM OXIDE AND MANGANESE OXIDE TO MAKE A ROSE COLOR CRYSTAL QUARTZ

LUSTER METALLIC- LOOKS LIKE METAL IN THE WAY THE MINERAL REFLECTS LIGHT (GALENA OR PYRITE)

NON-METALLIC- DOES NOT LOOK LIKE POLISHED METAL, SO OTHER TERMS ARE USED  VITREOUS- SHINY, GLASSLIKE (QUARTZ) • PEARLY LOOKS LIKE PEARLS WHEN LIGHT IS REFLECTED OFF OF THE SURFACE (OPAL)

 WAXY- DULL SHINE LIKE CANDLE WAX (SULFUR, OLIVINE)  EARTHY- NO SHINE AT ALL (BAUXITE)  ADAMANTINE- BRILLIANT GLOW, BEAM OF LIGHT AT A CERTAIN ANGLE (DIAMOND)

STREAK HOW DO YOU FIND THE STREAK COLOR OF A MINERAL? THE COLOR OF A MINERALS POWDER HOW DO YOU FIND THE STREAK COLOR OF A MINERAL? RUB THE MINERAL AGAINST A STREAK PLATE AND OBSERVE THE POWDER’S COLOR

BREAKAGE PATTERN CLEAVAGE- TENDENCY OF A MINERAL TO SEPARATE ALONG PLANES OF WEAKNESS  ONE PLANE OF WEAKNESS BASAL CLEAVAGE (MICA)  TWO PLANES OF CLEAVAGE AT 90* (ORTHOCLASE)

 THREE PLANES OF WEAKNESS AT 90* = CUBIC (HALITE)  THREE PLANES NOT AT 90* = RHOMBOHEDRAL (CALCITE)

FRACTURE- NO PLANES OF WEAKNESS SO THE MINERAL BREAKS ALONG IRREGULAR SURFACES CONCHOIDAL- SURFACES ARE SOMEWHAT ROUNDED, SHELL-LIKE (QUARTZ)

UNEVEN- ROUGH SURFACE, NO DISTINGUISHABLE PATTERN  FIBROUS- JAGGED SURFACE LIKE FIBERS (WOLLASTONITE)

Hardness RESISTANCE TO BE SCRATCHED; IS VERY USEFUL SINCE A MINERAL’S HARDNESS IS CONSTANT • SCALE TO MEASURE HARDNESS WAS DEVELOPED BY FRIEDRICH MOH IN 1812 • HARDNESS IS MEASURED ON A SCALE FROM 1 BEING THE LOWEST TO 10 BEING THE HIGHEST. • TO DETERMINE THE HARDNESS OF A MINERAL YOU MUST TRY TO SCRATCH THE MINERAL AGAINST A GLASS PLATE

MINERAL NAME TYPICAL USES 1 2 3 4 5 6 7 8 9 10 TALC TALCUM POWDER, BABY POWDER GYPSUM BUILDING MATERIALS (SHEETROCK) FINGERNAIL IS A 2.5 CALCITE CEMENTS FLUORITE TOOTHPASTE APATITE FERTILIZER GLASS IS A 5.5 FELDSPAR FLOOR TILES QUARTZ WATCHES, ABRASIVES TOPAZ GEMSTONES (EMERALD) CORUNDUM GEMSTONES (RUBY & SAPHIRE) DIAMOND SAW BLADES, “AGIRL’S BEST FRIEND”