1 of 45

ROCKS & MINERALS

TOPIC 11

2 of 45

  • Minerals are the ingredients of rocks.

​

Or

​

  • Rocks are made up of minerals.

3 of 45

4 of 45

Minerals

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

5 of 45

6 of 45

Mineral Properties

  • Used to identify minerals

​

  1. Color
  2. Least useful property in identifying minerals.
  3. Why?

7 of 45

All of these are varieties of quartz!

8 of 45

  1. Streak
  2. The color of a minerals powder.
  3. “streak test”

9 of 45

  1. Luster
  2. How the minerals surface reflects light.
  3. Metallic vs. non- metallic.

10 of 45

  1. Hardness
  2. The ability of a mineral to resist being scratched.
  3. “Scratch test”

​

  • If mineral A can scratch mineral B, what does that tell us about the relative hardness of each mineral?

11 of 45

Moh’s Hardness Scale

Soft

​

​

​

​

​

​

Hard

12 of 45

13 of 45

5. Fracture/ Cleavage�

Fracture

  • Mineral breaks unevenly or irregularly

Cleavage

  • The tendency of a Mineral to break evenly along its weakest plane.

14 of 45

15 of 45

  1. Crystal Form
  2. Some minerals tend to form crystals that aid in the identification of the mineral.

16 of 45

  1. Specific Gravity
  2. 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 of 45

  1. Others
  2. Acid test – Calcite
  3. Magnetic – Magnetite
  4. Taste - Halite

18 of 45

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

19 of 45

Silicate Minerals

  • Minerals that contain a combination of silicon and oxygen.

​

​

​

Silicon-oxygen tetrahedron

The basic structural unit of silicate minerals

20 of 45

21 of 45

Rocks

Monomineralic

  • 1 Mineral

Polymineralic

  • More than 1 Mineral
  • Rocks are classified by how they are formed!!!

22 of 45

Sedimentary Rocks:

  1. Clastics
  2. Rocks that form when sediments (sand, silt etc.) are lithified.

Processes

  • Compacting and cementing
  • Vary due to grain size! (see ref tables p. 7)

23 of 45

24 of 45

  1. Non-Clastics
    1. Organics (bioclastics)
    2. Form from living things.

​

Examples: Coal, limestone

​

    • Chemical (crystaline)
    • Formed from the evaporation or precipitation of sea water.

​

Examples: Halite, gypsum

​

25 of 45

26 of 45

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 of 45

  • The longer the rock takes to cool, the larger the crystals!

​

  • Cools slow …..Large crystals
  • Cools fast …….small crystals
  • Cools immediately……NO Crystals (glass)

28 of 45

29 of 45

Vesicular- gas pockets

30 of 45

Metamorphic:

  • Rocks that are changed due to extreme heat and/or pressure.
  • DO NOT MELT!!! (they recrystalize)

​

Metamorphic rocks become…

    • Harder
    • More dense
    • Banded or foliated
    • Distorted

31 of 45

Banding

32 of 45

Foliated

33 of 45

Regional Metamorphism

  • Occurs when large areas of rock are changed.
  • Usually deep below the surface where crustal plates collide.

​

  • The Adirondacks!

34 of 45

Contact Metamorphism

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

35 of 45

36 of 45

Bedrock Of New York State

37 of 45

38 of 45

39 of 45

Identifying Characteristics of Rocks

Igneous

  • Intergrown crystals
  • Glassy texture

Sedimentary

  • Cemented fragments (sediments)
  • Fossils
  • Organic material

Metamorphic

  • Banding
  • Foliated

40 of 45

41 of 45

The Rock Cycle

42 of 45

43 of 45

44 of 45

BONUS:

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

45 of 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