How Minerals Form

download report

Transcript How Minerals Form

How Minerals
Chapter 4 Sec 2
Minerals Form in Two Ways
Crystallization of
Melted Materials
(i.e. magma and
Crystallization of
Dissolved in Water
(In Solution)
 Crystallization:
the process by
which atoms are arranged to form
a material with a crystal shape…..
 Note: Fully formed crystals are
rare- most are only partially
formed because they form the
same time as others
Crystallization of Melted Materials
(Magma & Lava)
Magma Cools inside the crust or lava
hardens and cools on the surface of
These liquid crystals cool and form
crystals (repeating pattern of atomseither elements or compounds)
Size depends on ….
3 Things Impact the Size of the Crystals
Rate at which magma/lava cools
Slow=large crystals-tend to be deep below the
Fast=small crystals-on or near surface- crystals don’t
have enough time to add more to the repeating
Amount of Gas Magma Contains
Lots of gas interferes with the atom’s ability to
connect together
Chemical Composition of Magma
Compounds form bigger crystals than elements
A solution is…
mixture in which one substance
(the solute) is dissolved in another
(the solvent).
Minerals can form 2 Ways from a
 1.
materials dissolved in solution come
out of solution
 2. the solvent evaporates-leaving the
minerals behind
Crystallization of Materials
Dissolved in Water (in solution)
Elements dissolve in hot water heated by
the magma and form solutions
2. Solution cools
3. Elements and compounds leave the
solution and crystallize into minerals, often
forming veins
– Vein-narrow channel or slab of mineral
that is different from surrounding rock
Mineral Veins:
Mineral Solutions also occur near the midocean ridge:
1. Water seeps down through cracks in
ocean floor
2. It is heated by magma
3. Elements from the crust are dissolved
into solution
4. Rush upward due to density
5. Travels out of vents or chimneys
6. Cold water helps minerals crystallize
7. Mineral deposits are found on the
ocean floor
Hydrothermal Vents
Minerals Formed by Evaporation
 These
minerals are formed when the
water evaporates and leaves the
mineral that was in solution behind
 Examples:
–Deposits of Halite formed when
ancient seas evaporated
–Also, Gypsum, calcite, and potassium
Mineral Resources
Chapter 4 Sec 3
Uses of Minerals
used to make
useful products
gemstone is a hard, colorful mineral
that has a brilliant or glassy luster.
 Valued for their color, luster,
durability, and because they are rare.
 Called a gem once it is cut and
 Used for jewelry, decoration,
mechanical parts, grinding and
are the sources of
some metals- aluminum, iron,
copper, or silver
for their unique
properties of ductility,
malleability, and strength
Other Useful Minerals
 Medicines
 Fertilizers
 Building materials
Specific Examples
– talc=talcum powder
– Fluorite=used in aluminum and steel
– Calcite=microscopes
– Quartz-used to make glass, electronic equipment,
and watches
rock that contains a
metal or other
economically useful
Finding Useful Minerals
 Prospecting
–A prospector is anyone who
searches, or propsects, for an ore
–Look for Earth’s features- such as
types of rocks on the surface,
plants growing, and types of
elements found in water sources
Extracting Useful Minerals
3 types of mines
– Strip mine
 Earth moving equipment scrapes away soil to expose ore
– Open pit mine
 Miners dig an open pit mine to remove deposits and then
follow them below the surface (approx 1 km wide and
– Shaft mine
 To follow veins miners dig a network of tunnels (shaft
Mining can cause quiet a bit of damage to the
The process by which an ore is melted to
separate the useful metal from other
elements that the ore contains