2. A mineral:
1. Occurs naturally (not man-made)
2. is a solid
3. is a chemical compound arranged in an
orderly pattern (crystals)
4. is inorganic (not made from dead plants or
animals)
5. Is an element or a compound
What are minerals?
5. Physical Properties of Minerals
(can be used to identify the mineral)
Color
Can be misleading
Can vary with the type of impurities
6. Physical Properties of Minerals
(can be used to identify the mineral)
Luster
Surface reflection
metallic = shiny like
metal
non-metallic = dull,
non-shiny surface
Pyrite has a metallic luster
Calcite has a non-metallic luster
9. Physical Properties of Minerals
(can be used to identify the mineral)
Streak
The color of the powdered
form of the mineral
The color of the streak can be
different than the mineral
Minerals must be softer than
the streak plate
11. Breaking Properties:
Cleavage or Fracture
• Cleavage – mineral
breaks along a flat
surface or into
sheets
• Fracture – when a
mineral breaks
with lots of jagged
edges
12. Hardness = resistance to scratching
Hardness does not concern brittleness
(brittle = breaks apart easily)
e.g. glass is brittle (breaks easily when
dropped), but it is harder than copper, i.e.
it can scratch copper.
copper cannot scratch glass
Mineral test #1: hardness
13. Physical Properties of Minerals
(can be used to identify the mineral)
Hardness
How easily a mineral scratches
materials
Mohs Hardness Scale
• Scale from 1 (softest) to 10 (hardest)
• Test by seeing if the mineral can scratch
different objects (like human fingernail,
copper, penny, glass, steel file)
24. cleavage: tendency of a mineral to split
easily or separate along flat surfaces
e.g. mica: 1 cleavage
feldspar: 2 cleavages
calcite: 3 cleavages
galena: 3 cleavages
Mineral test #2: cleavage
25. Physical Properties of Minerals
(can be used to identify the mineral)
Cleavage & Fracture
• The way the mineral breaks
• Cleavage—minerals break
along smooth, flat surfaces
and every fragment has the
same general shape
• Fracture—minerals that break
at random with rough or
jagged edges
29. Specific gravity: “how dense is the mineral
compared to water?”
Nearly all minerals are denser than water.
Mineral test #3: specific gravity
30. If a mineral is denser than water, its
specific gravity is greater than 1.
If it is less dense than water, its specific
gravity is less than 1.
If it is equally dense as water, its specific
gravity equals 1.
specific gravity, cont’d
31. Extra Special Properties
1. Fluorescence
• Fluorescent color under ultraviolet (UV) light
2. Magnetic
• Attract magnets
3. Acid reaction
• Carbon dioxide gas bubbles off when you drop
acid on them
• Carbonates!