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Minerals lecture grade 7
MINERALS
Objectives:
1. Identify the
different minerals
2. Enumerate the
properties of
minerals
Minerals lecture grade 7
Minerals lecture grade 7
MINERALS ARE MADE UP OF SINGLE
ELEMENTS OR COMPOUNDS
ELEMENTS
COMPOUNDS
A SUBSTANCE THAT CANNOT BE BROKEN DOWN TO
ANY SIMPLER SUBSTANCE
ARE PURE SUBSTANCES THAT ARE THE UNIONS OF
TWO OR MORE 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%
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 EARTHS CRUST
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 QUARTZ
CONTAINS 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
POWDERS 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 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
FINGERNAIL IS A 2.5
GLASS IS A 5.5
1
2
3
4
5
6
7
8
9
10
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, AGIRLS 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)

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Minerals lecture grade 7

  • 2. MINERALS Objectives: 1. Identify the different minerals 2. Enumerate the properties of minerals
  • 5. MINERALS ARE MADE UP OF SINGLE ELEMENTS OR COMPOUNDS ELEMENTS COMPOUNDS A SUBSTANCE THAT CANNOT BE BROKEN DOWN TO ANY SIMPLER SUBSTANCE ARE PURE SUBSTANCES THAT ARE THE UNIONS OF TWO OR MORE 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%
  • 6. A MINERAL IS: 1.) NATURALLY OCCURRING 2.) DEFINITE CHEMICAL COMPOSITION 3.) INORGANIC SOLID 4.) CRYSTALLINE STRUCTURE 5.) DEFINITE SET OF CHEMICAL AND PHYSICAL PROPERTIES
  • 7. 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
  • 8. MOST MINERALS ARE COMPOSED OF TWO OR MORE ELEMENTS HALITE (NaCl) QUARTZ (SiO2)
  • 9. 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
  • 10. THE PHYSICAL PROPERTIES OF MINERALS ARE A REFLECTION OF THE INTERNAL ARRANGEMENT OF THEIR ATOMS
  • 11. 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
  • 12. METALLIC- LOOKS LIKE METAL IN THE WAY THE MINERAL REFLECTS LIGHT (GALENA OR PYRITE) - THE WAY A MINERAL SHINES IN REFLECTED LIGHT.
  • 13. 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)
  • 14. 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)
  • 15. THE COLOR OF A MINERALS POWDER RUB THE MINERAL AGAINST A STREAK PLATE AND OBSERVE THE POWDERS COLOR HOW DO YOU FIND THE STREAK COLOR OF A MINERAL?
  • 16. 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)
  • 17. THREE PLANES OF WEAKNESS AT 90* = CUBIC (HALITE) THREE PLANES NOT AT 90* = RHOMBOHEDRAL (CALCITE)
  • 18. FRACTURE- NO PLANES OF WEAKNESS SO THE MINERAL BREAKS ALONG IRREGULAR SURFACES CONCHOIDAL- SURFACES ARE SOMEWHAT ROUNDED, SHELL-LIKE (QUARTZ)
  • 19. UNEVEN- ROUGH SURFACE, NO DISTINGUISHABLE PATTERN FIBROUS- JAGGED SURFACE LIKE FIBERS (WOLLASTONITE)
  • 20. 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
  • 21. FINGERNAIL IS A 2.5 GLASS IS A 5.5 1 2 3 4 5 6 7 8 9 10 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, AGIRLS BEST FRIEND MINERAL NAME TYPICAL USES
  • 22. EFFERVESCENCE ADDING HCL TO A MINERAL CAUSES IT TO FIZZ MAGNETIC THE ABILITY TO ATTRACT A MAGNET (MAGNETITE) TASTE HALITE
  • 23. ODOR SOMETIMES THE POWDER OF A MINERAL HAS A CERTAIN ODOR (SULFUR SMELLS LIKE ROTTEN EGGS) DOUBLE REFRACTION SPLITS LIGHT RAYS (CALCITE)
  • 24. 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)