1. Minerals
8th grade

2. Mineral Groups 2 Major Groups
1. Silicate minerals – minerals that contain a combination of silicon and oxygen
a)Feldspar minerals – most common in Earth’s crust
Main part of all rocks on the Earth’s surface contain silicate minerals (ex. granite)
b) Quartz – 6 sided crystalline form; most common mineral in sand
c) Mica – soft and shiny; thin sheets
d) talc – softest known

3. 2. Nonsilicate Minerals – do not contain a combination of silicon and oxygen; usually classified by a chemical composition
a) Native Elements – minerals with only one element
b) Carbonates – contain combinations of carbon and oxygen (ex. limestone, cement, building stones)
c) Halides – inorganic materials containing combinations of fluorine, chlorine, iodine or bromine with sodium, potassium, or calcium (ex. halite, fertilizers, and photographic film)
d) Oxides – compounds that contain oxygen and 1 other element (ex. iron, aluminum)
e) Sulfates – contains sulfer and oxygen (ex. gypsum and plaster of paris)
f) Sulfides – contain sulfer and 1 or more metals (ex. pyrite)

4. Mineral Properties
Many minerals can be identified by physical properties.
Identifying minerals requires using at least 2 of the following properties:
Color
Luster – way surface reflects light
Metallic – shiny luster
Nonmetallic – not shiny, no reflection
Hardness – resistance to being scratched that depends on strength of bonds between ions or atoms of a mineral
Strongest mineral = diamond
Scale of hardness = Mohs – mineral rubbed against surface of each on scale

5. Mineral Properties
Streak – color of the powder left by a mineral when it is rubbed against a hard, rough surface (hardness 7); better to identify than color
Cleavage – tendency to split along set of parallel, flat surfaces
Fracture – tendency to break along irregular surfaces
Density – mass in grams/volume in cm3

6. Special Mineral Properties
Taste – unsafe to use this property because many minerals are toxic
Smell – strongest when just dug out of the Earth or struck
Reactions to hydrochloric acid – to see if made of calcite
Flexibility – able to bend thin layers with out breaking (ex. biotite and chlorites)
Magnetic – ex. magnetite
Lodestone= piece of magnetite that acts like a magnet

7. Special Mineral Properties
Fluorescence – glow and change color under ultraviolet light
Phosphorescence – continue to glow after ultraviolet light is no longer on them
Refraction – bending of light waves due to change in wave’s speed as it passes through 2 substances
Double refraction – ability of a mineral to produce 2 images
Feel – jagged; smooth; greasy or oily
Radioactive – ability to give off nuclear radiation as a result of a change in the atom’s nucleus (ex. uranium, radium, zircon)

8. Uses and importance of minerals
Metals –
good conductors of heat and electricity
useful in electric wires
make pots and pans for cooking
high melting points
malleability – ability to be shaped or formed by hammering or pressure (ex. aluminum, gold, silver, copper)
ductility – ability to be drawn or pulled into wire (ex. copper or gold)

9. Uses and importance of minerals
Native metals – metals not combined with other elements
Ore – naturally, occurring rock from which a useful metal or mineral is recovered.
Contain metal ions combined with other elements such as oxygen or sulfur
Extracting methods – separation with magnets, electricity or heating to high temperatures in the presence of carbon or carbon monoxide

10. Uses and importance of minerals
Alloys – minerals made of 2 or more metals or of a metal and a nonmetal; most important industrial material
1st to be discovered – bronze (alloy of copper and tin)
resist corrosion
have low melting points