1. Read pages 192 – 200 in blue book, and Section F, pages 118-138
in packet from Prentice-Hall (brown) book
When finished with reading, begin working on the minerals vocabulary

2. Geology!

3. What is Geology?
Geology is the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them. It includes the study of organisms that have inhabited our planet. An important part of geology is the study of how Earth’s materials, structures, processes and organisms have changed over time.

4. Minerals … Why study ‘em?
Building blocks of planet
Industrial minerals
Ore minerals
Energy resources
Gems
Environmental hazards

5. So, then what is a rock? What is a mineral?
Hematite
Homogeneous
Naturally occurring
Inorganic Solid
Definable chemical composition
Orderly arrangement of atoms in a lattice
Quartz
So, then what is a rock?
A rock is an aggregate of one or more minerals.
Granite, an igneous rock
Sandstone, a sedimentary rock
Gneiss, a metamorphic rock

6. What is a crystal?
A piece of homogeneous solid substance having a natural geometrically regular form with symmetrically arranged plane faces.
Halite
Quartz

7. Crystals have an orderly arrangement of atoms or ions
The shape of the crystal reflects the internal atomic structure.
Halite crystals
Atomic structure of Halite

8. Properties used to identify minerals
Luster
Color
Streak
Hardness
Crystal Form
Cleavage
Special Properties
Specific Gravity

9. Luster Describes how a mineral reflects light
Metallic minerals have the luster of polished metal

10. Luster Describes how a mineral reflects light Nonmetallic
“Vitreous” (glass-like)
“Dull” or “Earthy”
“Pearly”

11. Luster Describes how a mineral reflects light Nonmetallic “Greasy”
“Silky”
“Waxy”

12. Color Often not reliable! Except for some… May result from impurities
Olivine = olive green
Sulfur = yellow

13. S t r e a k Color of the mineral when in powdered form Streak color
Varieties of Hematite streak reddish-brown
White
Streak
Plate

14. of a minerals resistance
Moh’s Hardness Scale
Soft
Hardness is a measure
of a minerals resistance
to being scratched.
It is determined using
the “scratch test.”
Moh’s Scale is based on
a relative scale based
on minerals and
common materials.
1) Talc
2) Gypsum
-- fingernail at 2.5
3) Calcite
-- copper (old penny) at 3.5
4) Fluorite
5) Apatite
-- nail
6) Feldspar
-- streak plate or good steel file at
over 6.5
7) Quartz
8) Topaz
9) Corundum
10) Diamond
Hard

16. Tendency of a mineral to break on flat planes of weakness.
Cleavage
Tendency of a mineral to break on flat planes of weakness.

17. Cleavage vs. Crystal face
Cleavage planes repeat
No repetition of crystal face within crystal
Crystal
Faces
Crystal
Faces
Cleavage
Planes

18. Cleavage example in Calcite
Planes of cleavage are parallel to each other
Notice the double refraction
Cleavage example in Calcite
Cleavage planes look like box that has been pushed over 18

19. Notice how this sample shows many crystals grown together
Cleavage
in Halite
(salt)
Cleavage planes
Cubic cleavage
Two directions
at 90
Notice how this sample shows many crystals grown together

23. Minerals Lab Activity

24. Feldspar – Sample A

25. Quartz – Sample B

26. Calcite Sample D

27. Fluorite Sample E

28. Hematite Sample G

29. Gypsum Sample H

30. Magnetite Sample I

31. Muscovite Mica Sample J

32. Talc Sample L