minerals

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minerals

• Week 3 term 3

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Size is everything
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What are minerals?

• Mineral is a naturally occurring, inorganic
  solid that has a crystal structure and a definite
  chemical composition.
• Naturally occurring means that nature has to make
  it. Things like steel, bricks, glass, plastic are
  not naturally occurring and can not be a mineral.
  
• Inorganic not formed from living things or the
  remains of living things.

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Other things needed to be a mineral

• Solid, a mineral is always a solid.
• Crystal structure, the particles of the mineral
  line up in a pattern that repeats over and over
  again.
• Definite chemical composition, this means that a
  mineral always contains certain elements that are
  in a definite proportion.
• Almost all minerals are compounds. Example is
  quarts. It 1 part silica and 2 parts oxygen.

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How to identify minerals.

• Today geologist recognize about 3,800 different
  types of minerals. With so many it can be over-
  whelming to tell them apart.
• Each mineral has characteristics properties that
  can be used to identify it. Learning theses thing
  can help you to identify many different common
  elements present around you.

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The ways!!

• Color the color of a mineral can easily seen but
  is not a good way to positively identify a
  mineral. There are few minerals that have a very
  specific color and they are the only ones to have
  that color.
• Example gold, pyrite, and chalcopyrite are all
  gold. And malachite is always green, azurite is
  always blue. No other minerals look quite like
  these.

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The ways!!

• Streak is the color of a minerals powder as its
  streaked along unglazed tile. Surprising the
  streak and the color are often different.
• Example pyrite is always a gold color but its
  streak is greenish black.
• Luster is how light is reflected from the
  material. Minerals containing metals often are
  shiny, other terms used are glassy, waxy, earthy,
  pearly.

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The ways continued!!!

• Density Each mineral has a characteristic
  density. Density is the mass in a given space, or
  mass per unit volume.
• If you have two different samples that are the
  same size you can tell the one with more density
  because it will be heavier.
• Example galena is much more dense than quartz.
  The same size sample of galena will weigh three
  time as much as the quartz.

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The ways still continued!!!

• Hardness hardness is one of the best ways to
  determine a minerals identity. In 1812 an
  Austrian named Fredric Mohs. Came up with a scale
  of hardness called Mohs hardness scale.
• This scale consists of 10 different minerals in
  increasing hardness. It ranks them from the
  softest to the hardest.
• Hardness is determined by the scratch test. A
  mineral can scratch any mineral softer that its
  self. But can be scratched by any mineral hard
  than it as well.

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Hardness contined
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Hardness still continued!!

• To determine the hardness of a mineral not on the
  scale, you could use minerals on the scale to
  find its hardness.
• Example azurite isn't ion the scale if you tried
  to scratch it with talc(1) or calcite(3) it wont
  scratch but Apatite(5) will so its hardness is
  about 4.

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Crystal system

• Each mineral has a way the crystal will grow.
  This is done at the atomic level. Atom by atom
  the structure takes form. There are six different
  forms.
• Cubic
• Hexagonal
• Tetragonal
• Orthorhombic
• Monoclinic
• Triclinic

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Cleavage and fracture

• Cleavage a mineral that splits easily along a
  flat surfaces.
• Example mica
• Fracture minerals that do not split apart
  evenly, instead they have a characteristic type
  of fracture.
• Examples obsidian, quartz

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This examples of rock cleavage
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This is examples of rock fracture
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How minerals form.

• They from by crystallization . This can happen
  two ways. Crystallization of lava or magma and
  the crystallization of dissolved minerals in
  water.
• Crystallization is the process by which atoms
  are arranged to form a material with a crystal
  structure.

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Minerals from lava and magma

• Minerals form as hot magma cools inside the
  crust, or as lava hardens on the surface. When
  these liquids cool to a solid state, they form
  crystals.
• To get a larger crystal you need time for them to
  grow. If the magma has thousands of years you can
  get some vary large crystals.
• If the molten material cools quickly then the
  crystals wont have time to grow so you end up
  with small or no crystals.

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Minerals from solution

• A solution is a mixture in which one substance
  is dissolved into another. When the elements and
  minerals that are dissolved in the solution leave
  then crystallization occurs.
• This usually happens by evaporation then the
  solutes are left to crystallize,
• Example rock salt out at the great salt lake.
• The other way is from hot water. Magma can heat
  water enough to dissolve metals into it. Then as
  it cools the metal will solidify usually in a
  vein.
• Examples silver and gold.

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Minerals uses.

• How do we use minerals?
• There are many different ways, depending on the
  mineral. If it is a metal or a precious gem then
  we can cut and from it into jewelry. If it
  essential to our life functions then we need to
  eat it.
• Can anybody think of a mineral that is essential
  for us to live?
• Examples salt, Iron, calcium, and many others.
  
• Can you think of any other uses?
• Are there any questions?
• Get ready for the quiz.

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Quiz

• 1. What is a mineral?
• 2. Why are mineral important?
• 3. Who was the man that come up with the hardness
  scale?
• 4.How many crystal formations type are there?

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Quiz continued.

• 5. What is an essential element?
• 6. List 2 examples of essential minerals.
• 7. How many things are there that you must have
  to be a mineral?
• 8. List 3 of the thing that you must have to be a
  mineral.

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Quiz continued

• 9. About how many minerals out there that
  scientist recognize?
• 10. What is fracture and cleavage?
• 11. Give an example of fracture.
• 12. Give an example of cleavage.