Minerals are naturally occurring inorganic elements or compounds that have distinct physical and chemical properties. Rocks are composed of one or more minerals. Minerals can be identified based on properties like color, streak, luster, hardness, fracture/cleavage, crystal form, specific gravity, and other characteristics. Common rock types include sedimentary rocks such as sandstone, igneous rocks like granite, and metamorphic rocks like gneiss. The rock cycle illustrates how rocks continuously change from one type to another over geological time.

1. ROCKS & MINERALS
TOPIC 11

2. • Minerals are the
ingredients of
rocks.
Or
• Rocks are made
up of minerals.

4. Minerals
• Defn: naturally occurring, inorganic
elements or compounds with specific
physical and chemical properties.

6. Mineral Properties
 Used to identify minerals
1. Color
• Least useful property in identifying
minerals.
• Why?

7. All of these are varieties of quartz!

8. 2. Streak
• The color of a minerals powder.
• “streak test”

9. 3. Luster
• How the minerals surface reflects
light.
• Metallic vs. non- metallic.

10. 4. Hardness
• The ability of a mineral to resist being
scratched.
• “Scratch test”
• If mineral A can scratch mineral B, what
does that tell us about the relative
hardness of each mineral?

11. Moh’s Hardness Scale
Soft
Hard

13. 5. Fracture/ Cleavage
Fracture
• Mineral breaks
unevenly or
irregularly
Cleavage
• The tendency of
a Mineral to
break evenly
along its weakest
plane.

15. 6. Crystal Form
• Some minerals tend to form crystals that
aid in the identification of the mineral.

16. 7. Specific Gravity
• The ratio of the density of the mineral to
the density of water (1 g/cm3)
• If a mineral has a specific gravity of 5
that means it is 5 times as dense as
water.

17. 8. Others
• Acid test – Calcite
• Magnetic – Magnetite
• Taste - Halite

18. A minerals properties are
due to the internal
arrangement of its atoms.

19. Silicate Minerals
• Minerals that contain a combination of
silicon and oxygen.
Silicon-oxygen tetrahedron
The basic structural unit of silicate minerals

21. Rocks
Monomineralic
• 1 Mineral
Polymineralic
• More than 1 Mineral
 Rocks are classified by
how they are formed!!!

22. Sedimentary Rocks:
1. Clastics
• Rocks that form when sediments (sand,
silt etc.) are lithified.
Processes
• Compacting and cementing
• Vary due to grain size! (see ref tables p.
7)

24. 2. Non-Clastics
A. Organics (bioclastics)
• Form from living things.
Examples: Coal, limestone
B. Chemical (crystaline)
• Formed from the evaporation or precipitation
of sea water.
Examples: Halite, gypsum

26. Igneous:
- Form when liquid rock cools and solidifies
Intrusive
• Cools below the
earths surface
(slowwwwly!)
• Magma
• “Plutonic”
Extrusive
• Cools at the Earths
surface (quickly!)
• Lava
• “Volcanic”

27. The longer the rock takes to cool, the
larger the crystals!
• Cools slow …..Large crystals
• Cools fast …….small crystals
• Cools immediately……NO Crystals (glass)

29. Vesicular- gas pockets

30. Metamorphic:
• Rocks that are changed due to extreme
heat and/or pressure.
• DO NOT MELT!!! (they recrystalize)
Metamorphic rocks become…
1. Harder
2. More dense
3. Banded or foliated
4. Distorted

31. Banding

32. Foliated

33. Regional Metamorphism
• Occurs when large areas of rock are
changed.
• Usually deep below the surface where
crustal plates collide.
• The Adirondacks!

34. Contact Metamorphism
• Occurs when liquid rock comes into
contact with other rocks.

36. Bedrock Of New York State

39. Identifying Characteristics of
Rocks
Igneous
• Intergrown crystals
• Glassy texture
Sedimentary
• Cemented fragments
(sediments)
• Fossils
• Organic material
Metamorphic
•Banding
•Foliated

41. The Rock Cycle

44. BONUS:
• CLASSIFY this rock as igneous,
sedimentary or metamorphic and
EXPLAIN why you classified it that way.

45. BONUS:
Name the mineral that has the following
properties:
• Non-metallic
• Can scratch fluorite but cannot scratch
quartz
• Exhibits cleavage
• Contains the elements sodium &
hydrogen