1. Chapter 5
Lithosphere
Rocks & Minerals

2. Minerals Fist List
High Five!!
What is a Mineral?

3. Solid, Earth Material What does that mean?!?!?!
--Not a gas or a liquid
--Has a definite shape and volume
Solid, Earth Material
QUESTION?
Is oil a mineral??
Answer…
No, because it is a liquid.

4. What does that mean?!?!?!
Naturally Occurring
--Not man-made

5. Inorganic What does that mean?!?!?! --Not formed from living
things or the remains of
living things
--NON-LIVING!!
EXAMPLES
Coal is NOT a mineral because it comes from plants.
Amber is NOT a mineral because it comes from tree sap.
A pearl is NOT a mineral because it comes from oysters.

6. Definite Chemical Formula
What does that mean?!?!?!
--The elements that make
up the minerals are combined
in definite proportions
Definite Chemical Formula
EXAMPLES
-Gold (Au)
-Pyrite (FeS²)
-Graphite (C)
-Diamond (C)

7. Definite Crystal Structure
What does that mean?!?!?!
--Atoms are arranged in a repeating pattern
--Each mineral has a different INTERNAL ARRANGEMENT OF ATOMS that gives it distinct physical and chemical properties
Definite Crystal Structure

8. What does that mean?!?!?! Definite Crystal Structure QUESTION ANSWER
How does the mineral graphite,
which is soft have the same
chemical formula as diamond,
which is the hardest mineral
in the world?
Definite Crystal Structure
ANSWER
Because their internal
arrangement of atoms are different

9. Minerals in Your House

10. How are Minerals Identified??
Fill in the spiders legs as we go!!

11. Minerals can be
identified by
their chemical
and physical
properties.

12. Classifications of Minerals
Silicate
Contains silicon, and oxygen
Make up 96%of Earth’s crust
Non Silicate
Make up 4% of Earth’s crust
Does not contain silicon or oxygen
Major classifications
Carbonates, halides, native elements, oxides, sulfates, & sulfides (know this list for the quiz)

13. Minerals are identified by their key characteristics
hardness
crystal shape (form)
luster
color
streak
cleavage/fracture
density (specific gravity)
special properties --reaction to acid --fluorescence salty taste magnetism

14. Color How are Minerals Identified?? --Least useful for identification
--One mineral can come in many colors
EXAMPLE:
--Hematite: Comes in black, red and brown

15. Color
results from ability to absorb some wavelengths and reflect others
some minerals have characteristics colors
others vary due to chemical differences or impurities (atoms mixed inside the main elements)

16. How are Minerals Identified??
1. Some minerals are always the same color
Sulfur
2. Some minerals can have many colors
Rose Quartz
Quartz
Smoky Quartz

17. Colors can vary as a result of…
Chemical Impurities– Cobalt compounds tend to be pink, purple, or blue
Manganese—tends to produce pink colors

18. Colors can vary as a result of…
B. Oxidation—exposure to air and water changing the color of the mineral.
Ex. Rust
--Iron is the dominant coloring agent in rocks and soils

19. Streak How are Minerals Identified??
--the color of a mineral when it is finely powdered
--determined by rubbing the mineral on a piece of tile
Streak
Hematite has a reddish-brown streak.

20. Streak
Color of the powder when rubbed on a “streak plate” (unglazed porcelain)
Some paint is based on powdered minerals (streaks).

21. Luster How are Minerals Identified??
--describes how a mineral appears to reflect light
There are 2 categories in which a minerals luster can fall…
Luster
Metallic OR Non-Metallic

22. Luster Describes how light reflects off the surface
Main categories are “metallic” and “non-metallic”
Non-metallic includes “dull,” glassy,” waxy,” “pearly,” and othershttp://

23. How are Minerals Identified??
A. Metallic– reflects light like metal (shiny)
Graphite
Galena
Pyrite

24. How are Minerals Identified??
B. Non-Metallic—any mineral which DOES NOT exhibit shiny metallic characteristics
Ex. Quartz

25. Metallic or Non-Metallic??
Mica
Pearly luster
Metallic
Magnetite

26. Metallic or Non-Metallic??
Pyroxene
Dull luster

27. Hardness How are Minerals Identified??
--Resistance of a mineral to being scratched
--Moh’s Hardness Scale—compares the hardness of the mineral to 10 reference minerals.
Hardness

28. Mineral Hardness Ability to scratch another mineral
Mohs Hardness Scale from 1 (talc) to 10 (diamond)
Quartz (most common mineral and most dust particles) is 7

29. How is Hardness Determined??
The scale consists of number 1 through 10; 1 being the softest and 10 being the hardest. Each number represents a different mineral- each harder than the previous. The 10 minerals are to the left.
Softest
Hardest

30. How is Hardness Determined??
Several common household items have a fixed hardness, and can be used to test for hardness.
-Fingernail = 2.5
-Copper penny = 3-3.5
-Nail = 4.5
-Knife blade = 5.5
-Glass = 5.5
-Steel file = 6.5
-Streak plate = 7

31. What Determines Hardness?
--Hardness is determined by a minerals internal arrangement of atoms.
Ex. Diamond vs. Graphite
-Diamond has hardness of 10 and graphite is ranked between 1 and 2. Diamond is about 40 times harder than graphite due to the way the atoms are arranged.
--Hardness is the best property to use to identify a mineral.

32. Cleavage or Fracture How are Minerals Identified??
Cleavage—when a mineral breaks along a flat, smooth surface
Cleavage or Fracture

33. Examples of Minerals that show Cleavage
Mica exhibits basal cleavage.
Galena exhibits cubic cleavage.

35. What Determines Cleavage and Hardness?
A minerals internal arrangement of atoms!!

36. How are Minerals Identified??
Fracture—When a mineral breaks along irregular rough surfaces.
EX. Quartz
Cleavage or Fracture

37. Mineral cleavage/fracture
Some minerals split along flat surfaces when struck hard--this is called mineral cleavage
Other minerals break unevenly along rough or curved surfaces--this is called fracture
A few minerals have both cleavage and fracture

38. Density or Heft How are Minerals Identified??
--The amount of matter in a given space (mass/volume)
Depends on…
-kind of atoms which make up the mineral
-how the atoms are arranged in the crystal lattice
Density or Heft

39. Density (Specific Gravity)
All minerals have density (mass / volume), but some are very dense
Examples include galena, magnetite, and gold
Specific Gravity is the density of the mineral compared with density of water (1g/ml)

40. Crystal Shape How are Minerals Identified??
--Minerals have a characteristic crystal shape resulting from the atomic packing of the atoms when the mineral is forming
Crystal Shape

41. Crystal Shape (Form)
External structure due to internal arrangement of the atoms
Six basic groups of shapes, with about three dozen variations

42. Special Properties How are Minerals Identified??
-Magnetism (Magnetite)
-Fluorescence & Phosphorescence
-Salty taste (Halite)
-Smell (Sulfur)
-Chatoyancy & Asterism
Special Properties

43. Special Characteristics-- Fluorescence & Phosphorescence
Some minerals will glow when placed under short-wave or long-wave ultraviolet rays (fluorenscence)
Some minerals will continue to glow when the light is turned off (phosphorescence)

44. Special Characteristics-- Salty Taste
DO NOT TASTE MOST MINERALS!
Halite is the exception--it will taste salty

45. Special Characteristics-- Magnetism
Many iron minerals will produce an invisible magnetic force field
“Lodestone” was used by Vikings more than 1,000 years ago as compasses

46. Special Properties Chatoyancy Asterism
Light reflects and gives the appearance of a “cat’s-eye”
Similar to Chatoyancy however, the effect is a 6 sided star shape