Download Mohs Hardness Scale

Minerals
A naturally occurring solid that
formed through inorganic processes
and has a specific chemical
composition and a definite
crystalline structure
Formation of Minerals
 (Quartz,
mica, feldspars,
hornblende, olivine, augite)
 (Talc, mica, garnet), and
solutions
 (Calcite, Halite, Gypsum, and
some Iron oxides)
Structure/Classification
1.
2.
3.
4.
5.
6.
Cubic – Halite or Fluorite
Tetragonal - Zircon
Orthorhombic – Olivine
Monoclinic – orthoclase
Triclinic - plagioclase
Hexagonal - calcite
Native Elements – 20%
 Metallic
ex: gold, silver, copper,
iron, platinum
 Metalloid
 Nonmetal
graphite
ex: arsenic, bismuth
ex: sulfur, diamond,
Silicates – 96% of min. in crust
 Oxygen
and Silicon and usually
one or more elements
 Examples – quartz and
feldspars
 Single-chains, Double-chains,
and Sheets
Carbonates


Carbonate ion
(CO3)2Calcite (CaCO3),
Dolomite (CaMgCO3)
Oxides
Compounds made of
Oxygen and one or more
metallic elements
 Magnetite, hematite,
corundum

Halides



Contain one or more metals and
a Halogen
Halogens include chlorine,
bromine, fluorine, iodine
Examples: Halite, Fluorite
Sulfates
Contain the sulfate ion
(SO4)2- and one or more
metallic elements
 Gypsum

Sulfides
Contains sulfur and
one or more metallic
elements
 Galena, pyrite

Identification

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

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


Color
Luster
Texture
Streak
Hardness
Cleavage and Fracture
Density
Specific Gravity
Color

Self explanatory
Luster
Metallic or Nonmetallic
http://webmineral.com/help/Luster.shtml
Texture






Smooth
Greasy
Rough
Soapy
Glassy
Ragged
Streak
 Can
be observed by rubbing
a mineral over an unglazed
piece of porcelain
Hardness
 How
easily a mineral is
scratched
 Mohs Hardness Scale
Mohs Hardness Scale
1
2
3
4
5
-
Talc
Gypsum
Calcite
Fluorite
Apatite
6 - Orthoclase
Feldspar
7 - Quartz
8 - Topaz
9 - Corundum
10 - Diamond
 On
the Mohs scale, fingernail
has hardness 2; copper penny,
about 3; a knife blade, 5;
window glass, 5.5; steel file,
6.5. Using these ordinary
materials of known hardness
can be a simple way to
approximate the position of a
mineral on the scale.
Think of an mnemonic for Mohs
Hardness Scale
 Some
mnemonics traditionally
taught to geology students to
remember this table are "The Girls
Can Flirt And Other Queer Things
Can Do" or "To Get Candy From
Aunt Fanny, Quit Teasing Cousin
Danny".
Cleavage and Fracture
 Mineral
that breaks along a
smooth line has
 Cleavage
 Mineral that appears to break
uneven has
 Fracture
Denstiy

Density = Mass / Volume
Specific Gravity
 Ratio
of the density of a
mineral compared to the
density of water at 4 degrees
Celsius