All minerals are formed by natural processes, which occur on or inside Earth with no input from...
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Transcript of All minerals are formed by natural processes, which occur on or inside Earth with no input from...
All minerals are formed by natural processes, which occur on or inside Earth with no input from humans Ex: Salt forms from the natural
evaporation of seawater (mineral-halite) Minerals are inorganic
Aren’t made by life processes Minerals are an element or compound
with a definite chemical composition Ex: Halite-NaCl (gives a distinct taste to
food)
Minerals are crystalline solids All solids have a definite volume and
shape Not all solids are minerals crystalline-atoms are arranged in a
pattern Graphite-arranged in layers Opal-not a mineral because it doesn’t
have a pattern
Is a solid in which the atoms are arranged in orderly, repeating patterns
Crystals with a smooth surface and regular shape developed in a freely open space Ex: clear quartz (hexagonal shape)
Crystals whose shape can’t be seen on the outside have developed in a tight space Ex: rose quartz
1. Hexagonal: Ex: Clear Quartz Surfaces form 120° and 60° angles
2. Orthorhombic- Ex: Barite Dimensions are unequal-brick like shape
3. Monoclinic: Ex: Orthoclase Unequal dimensions 1 right angle forms
4. Triclinic: Ex: rhodonite Exhibits the least symmetry Unequal in all dimensions
5. Cubic: Ex: Flourite Crystals are equal in size like a cube all three dimensions are equal6. Tetragonal: Ex: Zircon Like a cubic crystal One dimension is longer or shorter
than the other too
Natural processes form minerals 2 ways crystals form1.From Magma: Magma cools-atoms move closer
together Combine into compounds Atoms arrange themselves into orderly,
repeating patterns Type and amount of elements
determine which mineral will form
Size of crystals depends on how quickly magma cools
Large crystals form when magma cools slowly Small crystals form when magma cools quickly2. From Solution Crystals form from minerals dissolved in water Evaporation of H20 causes ions to come
together (halite) If too much of a substance is dissolved in
water, ions will come together forming crystals of that substance (don’t need evaporation)
8 elements form 98% of Earth’s crust Silicates
most rock-forming minerals belong to this group
Minerals that contain silicon, oxygen and one or more other elements
Silicon and oxygen 2 most abundant elements in Earth’s crust
Carbonates Contain carbon, and oxygen and other
elements Are rock-forming minerals
Every mineral has unique physical properties that distinguish them from each other
There are 7 properties scientists look at Every property you observe in a
mineral is a clue to its identity1.Mineral Appearance: Color and appearance Can not just look at these 2 properties
because minerals can have the same color and shape
2. Hardness How easily a mineral can be scratched Talc is soft and can be scratched with
your fingernail Diamonds are the hardest mineral Mohs scale
Lists the hardness of ten minerals Softest talc hardness =1 Hardest diamond=10 Depending on the item you can scratch the
mineral with, will tell you its value and what kind of mineral it is
3. Luster The way a mineral reflects light Can be metallic-shine like metal Can be nonmetallic-does not shine like metal
Ex: quartz, calcite, halite, flourite
4. Specific Gravity Is the ratio of its weight compared with the
weight of an equal volume of water Expressed as a number Ex: gold’s specific gravity=19 This means that it is 19 times heavier than
H2O
Heft is a term used to describe how heavy a mineral sample feels
5. Streak Is the color of a mineral when it is in a
powdered form Scratched on a piece of unglazed
porcelain tile Streak test only works if the mineral is
softer than the tile
6. Cleavage Minerals that break along a smooth,
flat surface Ex: Mica-breaks apart in smooth layers
7. Fracture Break with uneven, rough, or jagged
surfaces Ex: Quartz
Highly prized minerals because they are rare and beautiful
Most are special varieties of a particular mineral
Clearer, brighter or more colorful than original mineral
Table 2
Some gems are spectacular and play a role in history Ex: Cullinan Diamond
Was cut into 9 main stones and 96 smaller stones
Part of British crown jewels Ex: blue Hope diamond
Gained reputation for bringing bad luck
Some gems are useful Diamonds used as industrial abrasives
and cutting tools Rubies used to produce specific types
of laser light Quartz crystals used in electronics and
as timepieces Most industrial diamonds and other
gems are synthetic-made by humans
Mineral or rock is an ore if it contains a useful substance that can be mined at a profit
Ex: Hematite-contains iron Iron used to make pans, ships Aluminum comes from the ore bauxite Refining of aluminum
Aluminum oxide powder is separated from bauxite Powder is converted into molten aluminum by smelting-
substance is melted to separate it from unwanted materials that remain
Aluminum used to make bicycles, cans, foil
Mineral deposits left behind that fill in the open spaces created by weaknesses in rocks
Weaknesses include cracks, faults, and surfaces between layered rocks
Vein minerals fill in empty spaces after rocks collapse
Ex: Sphalerite Importance source of zinc-used in batteries
Titanium is a durable, lightweight, metallic element
Comes from minerals that have it Sources of titanium are ilmenite and
rutile Common in rocks that form when
magma cools and soldifies Titanium used to make cars, eyeglass
frames, golf clubs, bicycles, hip replacement