Notes: Minerals
What is a mineral?
Five Characteristics of Mineral
Naturally Occurring
A _____________ occurring, _____________ ___________ that
has a ______________ structure and a definite _____________
composition.
Now I See Crystal Clear!
► Naturally Occurring
► Inorganic (Was Never Alive)
► Solid
► Crystal Structure
► Chemical Composition
Must be _____________ by processes in the natural world.
Mineral Quartz forms naturally as molten material ________ and
hardens deep beneath Earth’s surface.
Are man made materials like Plastic, brick, glass, and steel can be
called minerals? _______
Mineral has to be Inorganic
Mineral is always a solid
Mineral has a crystal structure
A mineral can not form from organic materials (living things).
Is coal a mineral? _________, it comes from the remains of
plants that lived millions of years ago.
► Has definite volume and __________
A ___________ in which the atoms are arranged in a pattern that
repeats again and again.
A crystal has flat sides, called faces, that meets at sharp edges and
corners.
Mineral has a Definite
Composition
► Always contains certain element in definite proportions.
Quartz has ________ atom of silicon for every _______ atoms of
oxygen.
The most common minerals are:
quartz, feldspar, mica, and calcite.
Fact:
Over 60% of the Earth’s ___________ is made up of the family of
minerals known as feldspar!
Properties to identify, separate
and distinguish minerals.
Color
1.
2.
3.
4.
5.
6.
Color
Streak
Luster
Hardness
Cleavage/Fracture
Special properties
 Malleable or Ductile
 Magnetic
 Fluorescence
 Radioactive
 Taste
Color is the most __________ observed mineral property and the
least useful also.
Mineral azurite is always ___________. Mineral malachite is
Notes: Minerals
always _________.
Many minerals have a similar color.
Caution:
Many minerals have colors due to impurities, or they can change
colors in various circumstances.
For example, pure quartz is colorless or white, impurities can
make the mineral rose, purple or pink!
Streak of a mineral is the color of its _____________ when
rubbed on an unglazed white (porcelain) tile.
Streak
The streak is often not the ________ color as the mineral. A
mineral’s color may vary, but the streak rarely will!
Mineral sulfur has yellow color, but produces streak of
__________ color on black tile.
For example, Calcite occurs in many different colors, shapes, and
varieties. But every single variety of Calcite has a white streak. A
streak is useful in distinguishing two minerals with the same color
but different streak.
Minerals, which streak very light colors, can be easily identified
on black streak plate.
► The way a mineral reflects light from its surface.
Luster
The mineral (Galena) has a _____________
luster.
Topaz has a ____________ luster.
Quartz has a ____________________ luster.
Pearl has ______________ luster.
Malachite has __________ luster.
Earthy luster
Other terms that might be used include greasy, dull, and earthy.
Notes: Minerals
Vitreous or glassy luster
Hardness
The hardness of a mineral is it’s resistance to being scratched.
Diamond is the __________ of all minerals, and _______ is the
softest.
Friedrich Mohs devised a hardness _________. In this scale, ten
well known minerals are given numbers from one to ten.
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Cleavage
Talc is the softest and has a hardness of 1. A soft pencil
lead will scratch talc.
Gypsum is a bit harder and has a hardness of 2. A
fingernail scratches gypsum.
Calcite has a hardness of 3. A copper penny just scratches
it.
Fluorite has a hardness of 4. It can be scratched by an iron
or brass nail.
Apatite has a hardness of 5. It can be scratched by a steel
knife blade.
Feldspar has a hardness of 6. It will scratch a window
glass.
Quartz, with a hardness of 7, is the hardest of the common
minerals. It easily scratches hard glass and steel.
Topaz has a hardness of 8. It will scratch quartz.
Corundum has a hardness of 9. Corundum will scratch
topaz.
Diamond with its hardness of 10. It can easily scratch the
rest of the minerals.
► The cleavage of a mineral is it’s ability to split easily
along flat surfaces.
Cleavage can even be observed on ________ mineral grains
making it a very useful property!
Mica is probably the best example as it splits into ________
sheets. It is said to have one perfect cleavage.
Feldspar splits readily in two directions, always at or near right
angles.
Calcite and galena cleave in three directions. They are said to have
three good cleavages.
Fracture
► Not all minerals ________ cleavage.
► Those that don’t break along cleavage surfaces are said to
have fracture.
► Minerals ______________ in irregular way.
Notes: Minerals
Cleavage or Fracture
Crystal Shapes
Mica – __________________
Copper – _________________
Quartz – _________________
_____________________ mineral has the lowest harness and
___________ has the highest hardness .
► Crystal shape can be a useful property to identify minerals
if the minerals have had the time and space to _________
crystals.
 Most mineral grains that are found in rocks, _________
the room to grow.
Specific Gravity
► Specific gravity tells you how many times as __________
as water the mineral is.
► Pure gold can have a specific gravity as high as 19.3.
Acid Test
► Calcite is calcium carbonate, CaCO3.
► If a drop of weak hydrochloric acid is placed on calcite,
the ___________ bubbles as carbon dioxide is released.
Other Special Properties
Malleable or Ductile - Minerals that can be hammered thin or
shaped are said to show these properties.
Can you think of a mineral that might be shaped or hammered?
_____________
Magnetic - Some minerals that contain _________, are magnetic
and can be picked up by a magnet.
Fluorescence - This is the ___________of glowing while under a
ultraviolet light. Some minerals even glow once the light is turned
off!
Radioactive - Some minerals, such as this uraninite, are
radioactive. They give ___ subatomic particles that will activate a
Geiger counter.
Taste - Halite (rock salt) can be identified by its taste.
This practice is not recommended!