MINERALS ARE MADE UP OF SINGLE ELEMENTS OR COMPOUNDS

ELEMENTS 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

MOST MINERALS ARE COMPOSED OF TWO OR MORE ELEMENTS

HALITE (NaCl)

QUARTZ (SiO2)

• 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

* 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

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

LEAST USEFUL PROPERTY, CHANGE IN THE CHEMICAL FORMULA WILL VARY THE COLOR OF THE MINERAL. (QUARTZ)

SiO2

ROSE QUARTZCONTAINS TITANIUM OXIDE AND MANGANESE

OXIDE TO MAKE A ROSE COLOR CRYSTAL QUARTZ

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

- THE WAY A MINERAL SHINES IN REFLECTED LIGHT.

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)

EARTHY- NO SHINE AT ALL (BAUXITE)

ADAMANTINE- BRILLIANT GLOW, BEAM OF LIGHT AT A CERTAIN ANGLE (DIAMOND)

WAXY- DULL SHINE LIKE CANDLE WAX (SULFUR, OLIVINE)

THE COLOR OF A MINERALS POWDER

RUB THE MINERAL AGAINST A STREAK PLATE AND OBSERVE THE POWDER’S COLOR

HOW DO YOU FIND THE STREAK COLOR OF A MINERAL?

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)

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

FINGERNAIL IS A 2.5

GLASS IS A 5.5

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TALC TALCUM POWDER, BABY POWDER

GYPSUM BUILDING MATERIALS (SHEETROCK)

CALCITE CEMENTS

FLUORITE TOOTHPASTE

APATITE FERTILIZER

FELDSPAR FLOOR TILES

QUARTZ WATCHES, ABRASIVES

TOPAZ GEMSTONES (EMERALD)

CORUNDUM GEMSTONES (RUBY & SAPHIRE)

DIAMOND SAW BLADES, “AGIRL’S BEST FRIEND”

MINERAL NAME TYPICAL USES

• EFFERVESCENCE – ADDING HCL TO A MINERAL CAUSES IT TO FIZZ

• MAGNETIC – THE ABILITY TO ATTRACT A MAGNET (MAGNETITE)

• TASTE – HALITE

• ODOR – SOMETIMES THE POWDER OF A MINERAL HAS A CERTAIN ODOR (SULFUR SMELLS LIKE ROTTEN EGGS)

• DOUBLE REFRACTION – SPLITS LIGHT RAYS (CALCITE)

• SPECIFIC GRAVITY (DENSITY) – SOME MINERALS HAVE ATOMS VERY TIGHTLY PACKED, AND FEEL HEAVIER BECAUSE THEY ARE MORE DENSE (GALENA)

• FLUORESCENCE – THE ABILITY TO GLOW UNDER ULTRA VIOLET LIGHT (SPHALERITE)