WHAT IS A MINERAL?
A MINERAL IS A:
SOLID
NATURALLY OCCURING (made up
of elements)
INORGANIC
CRYSTAL SHAPE (unique to the
mineral)
CHEMICAL COMPOSITION
(elements bond together to make a
compound)
WHAT DOES THAT MEAN?
Naturally Occurring = NOT man-made
Inorganic = NOT made of/from a living thing
Crystal Shape = Repeating pattern of atoms
Chemical Composition = chemical formula
Ex: Quartz has a chemical formula of SiO2
NOT A MINERAL?
COAL IS NOT A
MINERAL, WHY?
It is not inorganic
because it formed
from the remains of
living organisms
It does not have a
crystal shape
NOT A MINERAL?
PEARL IS ALSO NOT A MINERAL, WHY?
Pearls are organic
because they are
made from
oysters.
They do not have a
crystal shape
NOT A MINERAL?
GLASS IS ALSO NOT A MINERAL, WHY?
Glass does not
a crystal shape.
NOT A MINERAL?
STEEL IS ALSO NOT A MINERAL, WHY?
1: It is man-made (not naturally occurring)
2: It does not have a chemical composition
because it is a mixture of iron and carbon
3: It does not have a crystal shape
“Diamonds are Forever” Reading
Before you Read:
Review the definition of a mineral (SNICC)
After you Read:
Answer these questions:
○ Can the LifeGem diamonds be considered true
minerals? Explain your answer.
○ How are these diamonds different than diamonds mined
out of the ground?
○ Would you want to use this company for yourself or for a
relative?
TWO GROUPS OF MINERALS
Silicate Minerals Nonsilicate Minerals
•Have both Silicon (Si) and •Do NOT contain Silicon and
Oxygen (O) elements in them Oxygen
•Make up more than 90% of • Dividing into different classes
Earth’s crust depending on elements in them
•Might have other elements in •Examples: Copper (Cu)
them as well Calcite (CaCO3)
Galena (PbS)
•Examples: Quartz (SiO2)
Talc Mg3Si4O10(OH)2
How do you Identify Minerals???
Translucent Delicate
Strong Smell
Sparkly
Color
Perfect Shapes
Texture
Mishapen – not perfectly
shaped
Hard
1. COLOR
Not reliable due to:
Impurities
Many minerals have same color
Some minerals have more than one
color
COLORS OF FLUORITE
2. HARDNESS
The ability of a mineral to resist
being scratched.
Relative to the hardness of other
minerals and objects
2 scales
Field hardness scale
Moh’s hardness scale
HARDNESS
FIELD HARDNESS
SCALE
Fingernail
Copper Penny
Steel Nail
Glass Plate
Steel File
MOH’S HARDNESS SCALE
1. Talc 6. Feldspar
2. Gypsum 7. Quartz
3. Calcite 8. Topaz
4. Fluorite 9. Corundum
10.Diamond
5. Apatite
3. LUSTER
The way a mineral reflects light
Either Metallic or Nonmetallic
Never described as “shiny” (that is
what luster means)
METALLIC
LUSTERS
Shines like a metal:
Chrome, Silver, Copper,
Gold, Bronze, Lead, etc.
NONMETALLIC LUSTERS
Brilliant (High Shine/Sparkly)
Pearly or Silky
Glassy(Vitreous)
Waxy/Greasy
Dull
Earthy
4. STREAK
Powdered residue left behind when
rubbed across a porcelain tile
Only works for minerals with a hardness
less than 7 (tile=7)
Streak may be different than outer color
More consistent/reliable than color
5. CLEAVAGE
The breaking of a
mineral along flat
surfaces
Can be 1,2, or 3
directional
3 Directions: Similar to
sides of a cube or
rhombus
Mica breaks into single sheets- 1 Directional
6. FRACTURE
Breaking of a mineral
in an uneven or
jagged fashion
“Splintery”-splits like
wood
“Earthy”/Uneven
“Conchoidal”-curved
“Fibrous”- like fibers
7. DENSITY
= Mass per volume (g/mL)
Every mineral has its own
unique density, regardless of its
size
○ Ex: The density of any piece of gold
will always be 19 g/mL
The density of any piece of silver
will always be 10.5 g/mL
8. CRYSTAL SHAPE
Microscopic shape of crystals
Slow cooling = larger crystals
Fast cooling = smaller crystals
Cubic, Hexagonal, Octagonal,
Rhomboid, Trapezoidal, etc
9. SPECIAL PROPERTIES
Magnetism (lodestone/magnetite)
Taste (Halite-salty)
Acid reaction (calcite)
Double refraction
Fluorescence (glow in UV)
Phosphorescence (glow continues)
Odor (Sulfur)
Radioactivity (Uraninite)
ScienceNow Diamond Factory
Diamond Factory Video
(click on “Watch Diamond Factory”)