MINERALS

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MINERALS
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MINERALS ARE MADE UP OF SINGLE ELEMENTS OR
COMPOUNDS
A SUBSTANCE THAT CANNOT BE BROKEN DOWN TO ANY
SIMPLER SUBSTANCE
ELEMENTS
EIGHT MOST COMMON ELEMENTS IN THE EARTHS CRUST
1.) OXYGEN 46 3-8.)THE REMAINING 25
IS
COMPOSED OF Al,
Fe, Ca, Na, K, Mg 2.) SILICON 29
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A MINERAL IS
1.) NATURALLY OCCURRING
2.) DEFINITE CHEMICAL COMPOSITION
3.) INORGANIC SOLID
4.) CRYSTALLINE STRUCTURE
5.) DEFINITE SET OF CHEMICAL AND PHYSICAL
PROPERTIES
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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
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MOST MINERALS ARE COMPOSED OF TWO OR MORE
ELEMENTS
HALITE (NaCl)
QUARTZ (SiO2)
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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 EARTHS CRUST
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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
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PHYSICAL PROPERTIES
THE PHYSICAL PROPERTIES OF MINERALS ARE A
REFLECTION OF THE INTERNAL ARRANGEMENT OF THEIR
ATOMS
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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
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LUSTER
- THE WAY A MINERAL SHINES IN REFLECTED LIGHT.
METALLIC- LOOKS LIKE METAL IN THE WAY THE
MINERAL REFLECTS LIGHT (GALENA OR PYRITE)
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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)
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? 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)
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STREAK
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 POWDERS COLOR
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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)
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? THREE PLANES OF WEAKNESS AT 90 CUBIC
(HALITE)
? THREE PLANES NOT AT 90 RHOMBOHEDRAL
(CALCITE)
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FRACTURE- NO PLANES OF WEAKNESS SO THE MINERAL
BREAKS ALONG IRREGULAR SURFACES

• CONCHOIDAL- SURFACES ARE SOMEWHAT
• ROUNDED, SHELL-LIKE (QUARTZ)

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• UNEVEN- ROUGH SURFACE, NO DISTINGUISHABLE
• PATTERN

? FIBROUS- JAGGED SURFACE LIKE FIBERS
(WOLLASTONITE)
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Hardness
RESISTANCE TO BE SCRATCHED IS VERY USEFUL SINCE
A MINERALS 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
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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, AGIRLS BEST FRIEND
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Special Properties

• EFFERVESCENCE ADDING HCL TO A MINERAL CAUSES
  IT TO FIZZ

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Special Properties
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Special Properties

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