Transcript Minerals (intro.)

Chapter 4
Basic Info on Minerals!
Mineral Video
http://www.youtube.com/watch?v=8a7p1NFn64s
Mineral Properties
• Inorganic
– Didn’t come from anything that was once alive)
• Solid (at room temp)
– Ice is not a mineral
• Naturally occurring
– Not man made
• Specific chemical composition
– May have some variations, but elements are same
throughout
• Definite crystalline structure
– Crystals may be microscopic due to rapid cooling
Mineral or Not?
• Coal
– Not
– It’s organic
• Diamond
– Mineral
• Dried mud
– Not
– No definite crystalline structure
Mineral or Not?
• Cubic zirconium
– Not (man-made diamond imitation)
• Salt
– Mineral
– NaCl, inorganic, cubic crystals
• Sugar
– Not
– Organic
• Copper
– Mineral
What are minerals made of?
• Minerals are made of …
– elements (Carbon, C, makes up diamonds),
– or …
– Compounds (quartz is made of silicon dioxide,
SiO2)
– Can you think of another example of minerals
made of compunds?
– Salt is made of sodium chloride
• (NaCl)
Minerals are the Building Blocks of Rocks
• Rocks are made of minerals
– Granite is made up of feldspar, quartz and often
other minerals
• There are thousands of minerals
• But only about 30 minerals are common
• Of the 30, 8-10 make up most of the rocks on
earth:
8 most common minerals
• Quartz
• Feldspar
• Mica
• Pyroxene
• Amphibole
• Olivine
• Garnet
• Calcite
Elements are Mineral Building Blocks
• The common rock-forming minerals are
mostly made up of the most common
elements in earth’s crust.
Most Common Elements in Earth’s Crust
– Oxygen (O)
46.6%
– Silicon (Si)
27.7%
Most Common Elements in Earth’s Crust
– Aluminum (Al)
– Iron (Fe)
5%
8.1%
Most Common Elements in Earth’s Crust
– Calcium (Ca) 3.6%
– Sulfur (S)
2.8%
Most Common Elements in Earth’s Crust
– Potassium (K) 2.6%
– Magnesium (Mg)
2.1%
How do Minerals Form? Part I
• What do you call the molten material that is
below the earth’s crust?
– Magma
• Which is less dense, magma or the
surrounding solid rock?
– Magma, so it is always pushing up on the crust
How do Minerals Form? Part I
• What kinds of places allow magma to rise?
– Volcanoes,
– places where the crust is separating and
– places where the crust is very thin (Yellowstone Park)
How do Minerals Form? Part I
• When magma rises and cools, it forms into
minerals
• Quick cooling  very small crystals
• Slow cooling  larger crystals
• Different magma composition  different
minerals
How do Minerals Form? Part II
• Often, minerals are
dissolved in water
– Ever heard of mineral
water????
• If the water contains
enough of the mineral, it
will begin to crystallize in
the water
Rock Candy = water saturated with sugar + time
How do Minerals Form? Part II
• We call water that contains so much mineral
that it crystallizes out to be…
– Supersaturated
• Also, crystals can form when the water the
mineral is in evaporates
Economic Minerals
• Minerals are everywhere and used for many
things
• Look around the room. Can you see anything
made of minerals?
• The ceiling is made from gypsum (wall board,
etc)
• Your pencil “lead” is graphite
• All metals are minerals
• Glass is melted down sand, essentially
• Computer chips are silicon
Economic Minerals
• A mineral is an _____ if it contains a useful
substance that can be mined at a profit
• ore
• _____ are minerals that are prized for their
rarity and beauty. Usually perfect crystals
• gems