MINERALS
http://www.youtube.com/watch?v=TYvye0CVbU0
Matter
• anything that has mass and takes up space
• Matter is composed of elements
Element• A substance that cannot be broken down
into simpler substances by ordinary chemical means
Composition of Earth’s Crust
ESRT Page 1
A grouping of atoms - Molecule
Most common molecule in Earth’s crust • Silica Tetrahedron
Composed of …
1 silicon atom
4 oxygen atoms
Silica Structure
4 oxygen atoms for every 1 silicon atom
Olivine
Feldspar, Quartz
Micas
Amphibole (Hornblende)
Pyroxenes (Augite)
Complexity Temp.
MINERALS• Naturally occurring• Inorganic (never
alive)• Definite chemical
composition• Crystal structure
because of the internal arrangement of atoms
A mineral is the building block of rocks
Native Minerals– Made of single
elements• Gold (Au)• Copper (Cu)• Sulfur (S)
Compound Minerals– Made of two or
more elements• Silicate Family
– A compound of silicon and oxygen
– 90% of the Earth’s crust is composed of silicates
Examples:–
Quartz SiO2
–Olivine (Fe,Mg)2Sio4
Chemical formula:
CChemical formula:
C
Graphite Diamond
How can 2 minerals with the same composition be so different?
What’s the point here?
“Internal Arrangement of Atoms” controls most physical properties!
MINERAL PROPERTIES FOR IDENTIFICATION
a. Color
Least dependable property because some minerals have lots of different colors
b. Luster
Appearance of the mineral surface in reflected light, how the mineral shines
Metallic – looks like a metal Non-Metallic
c. Hardness
• Resistance to being scratched
• https://www.youtube.com/watch?v=b7ANcWQEUI8
Moh’s Hardness Scale
softest
hardest
d. Streak
• Powdered form of a mineral, more reliable than color
e. CleavageTendency of minerals to split along repeated
smooth, flat planes.
Look for places where the mineral might have split along flat and sometimes shiny planes that usually reflect light well.
Look for stairsteps, sheets, squares, cubes
e. FractureMineral breaks has a jagged or lumpy, irregular appearance
f. Crystal shape• Geometric pattern
that a lone crystal of the mineral will have
SPECIAL PROPERTIES
Fluorescence – mineral glows under a black light
Double refraction
Magnetism – some minerals are attracted to a magnet
Taste – DO NOT EVER TASTE A MINERAL
Reaction to acids
Calcite and Dolomite will bubble when Hydrochloric Acid
All mineral properties are determined by
• The internal arrangement of atoms
ROCK
Composed of one or more minerals
Classified by
1. Origin – how they were formed
2. Mineral Content
3. Texture
3 Types
• Igneous
• Sedimentary
• Metamorphic
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