HPU NCS2200 earth science for elementary education majors summer 2104 online class rocks and minerals lecture

1. Minerals & Rocks

2. What is a Mineral?
 The building block of rocks
 Naturally occurring (versus synthetic)
 Inorganic (no C-H bonds)
 Solid (ice is a mineral then, but water is not)

3. What is a Mineral?
 Chemical composition & crystalline structure
are the two most important properties of a
mineral
 Elements
 fundamental component of matter
 Cannot be broken down by ordinary means
 88 naturally occurring elements in Earth’s
crust

4. Elements of the Earth
 8 elements make up
98% of Earth’s crust
 Oxygen
 Silicon
 Aluminum
 Iron
 Calcium
 Magnesium
 Potassium
 Sodium

5. Elements of the Earth
 Some few elements ARE minerals (eg: gold)
 Most are comprised of 2 to 5 elements
 Held together by + / - electrical charges
 Many can vary a little is components
 88 elements form over 3,500 minerals
 9 rock-forming mineral groups

6. Crystals: the crystalline
nature of minerals
 Crystal – any substance whose atoms are
arranged in a periodic, repeating pattern
 This pattern is crystalline structure
 Unit cell – the smallest group of atoms making up
the unique pattern
 Crystal face – flat surface occurring when a
crystal grows freely
 Reflects light
 Bonding creates crystal structure

7. Crystal Structures

9. Physical properties of minerals
 Crystal habit
 the way crystals aggregate
 Cleavage
 Some minerals tend to break along flat surfaces
 Fracture
 The way a mineral breaks other than cleavage

10. Physical properties of minerals
 Hardness – Moh’s scale
 1 to 10, based on
minerals
 Specific gravity
 Density relative to water
 Color
 Obvious, but limited use
 Streak
 Color of fine powder
 Luster
 The manner it reflects
light
 “Other” properties

11. Mineral classes and
rock-forming minerals
 Silicates
 Carbonates
 Sulfides
 Sulfates
 Native elements
 Halides
 Oxides
 Hydroxides
 Phosphates

12. Mineral classes and
rock-forming minerals
 Silicates
 Most abundant rock-
forming minerals
 Carbonates
 Form many sedimentary
rocks
 Phosphates
 Turquoise
 Hydroxides
 Bauxite
 Halides
 Table Salt
 Sulfates
 Gypsum
 Sulfides
 Pyrite
 Oxides
 Hematite
 Native Elements
 Gold, Silver

13. Silicate minerals compose 92% of Earth’s Crust

14. Igneous
 Intrusive (inside)
 Cool slowly
 Forms from molten
magma
 Has visible (large)
crystals
 Ex: granite/quartz
 Extrusive (outside)
 Cool quickly
 Forms from lava
 Has invisible (small)
crystals
 Ex:
basalt/pumice/Rhyolite
Formed from cooling magma

15. Metamorphic
(large – change)
 Formed by heat and pressure (physical) OR
 By chemical changes which occur through
reaction between rock and outside chemical
 Two types of metamorphism:
 Contact and regional
 Contact happens under the surface when magma
intrudes into the rock
 Regional happens on the surface from intense heat and
pressure usually during mountain building

16. Metamorphic
Coquina Marble

17. Metamorphic
 Two types form different characteristics
 Foliated have visible bands
 Ex: gneiss and slate
 Non-Foliated have no visible bands
 marble

18. Sedimentary
 Formed from Sediment
created by weathering and
erosion of existing rocks
which is then compacted
and cemented
 Weathering and erosion
 Particles, altered, or dissolved
materials
 Transported and deposited
 Compaction
 Lithification (“glueing”
together)
 Four Types
 Clastic
 Chemical
 Organic
 Bioclastic

19. Clastic
 Easily seen
fragments
 Conglomerate
 Rounded particles
 Breccia
 Angled particles
 Not easily seen
fragments
 Sand sized
 Sandstone
 Clay sized
 Shale/siltstone

20. Chemical
 Formed by Chemical
Processes
 Evaporation
 Solid forms when
water is evaporated
 Halite (salt)/Gypsum
 Precipitate
 Forms when two
liquids are mixed
 limestone

21. Bioclastic
 Are formed from
living organisms
 shell fragments
 Hard-shelled
organisms
 Clams, corals, oysters,
etc.
 Carbonate skeletons

22. Organic
 Formed from living
organisms -
plants/animals
 Coal made from
plants
 Limestone made
from shells

23. Rock Cycle
Magma
Igneous
Weathering
& erosion
sedimentsSedimentary
Rock
Metamorphic
Rock
Heat &
Pressure
Compaction &
cementation
Heat &
Pressure
Weathering
& erosion

24. Videos
 This is a super website for mineral
identification
 http://www.rocksforkids.com/RFK/identificati
on.html#Field