CHAPTER 4

MINERALS!

Page 84 in your book

Fascinating Fact The elements oxygen, silicon,

aluminum, iron, magnesium, calcium, potassium, and sodium make up 99 percent of all minerals on Earth

4.1 What in the heck is a mineral? = A naturally occurring, inorganic solid

that has a specific chemical composition and a definite crystalline structure.

* Minerals are the building blocks of rocks!

Mineral Characteristics 1. naturally occuring and inorganic 2. definite crystalline structure 3. solids with specific compositions

“1. Naturally occurring and inorganic”

Formed only by NATURAL PROCESSES

INORGANIC = not alive and never was alive! Ex – sugar is NOT

a mineral because it came from a plant that was ALIVE!

“2. Definite Crystalline Structures” Crystal is a solid in which the atoms are arranged in repeating patterns.

“3. Solids with specific compositions”

must be an actual solid! And , must have the unique arrangement

and correct proportions to be considered a mineral.

Ex – NaCl

Get 4 Pieces of paper! We are going to make a mineral flipbook

for identification purposes! (like on page 85)

Step #1- slide your four papers up. Step #2 – Fold the bottom half UP

toward the top Step #3 – Staple them on the crease! Step #4 – now label them like page 85 And then we will fill in the characteristics

as we go!

Mineral I.D. Characteristics! 1. Color 2. Luster 3. Texture 4. Streak 5. Hardness 6. Cleavage and Fracture 7. Density and Specific Gravity

1. Color One of the most noticeable

characteristics Color can be due to trace elements or

compounds. One of the least reliable clues of a

mineral’s ID

2. Luster MetallicShinyReflects light

Nonmetallic Not shiny Dull – due to

chemical composition

3. Texture = How a mineral feels to the touch Con = Subjective to the tester Ex – smooth, rough, ragged, greasy, or

soapy

4. Streak When a mineral is rubbed across an

unglazed porcelain plate it leaves a colored powdered streak. Only if the mineral is softer than the p. plate!

Nonmetallics typically leave a white streak Useful for Metallics ID

5. Hardness = Measure of

how easily minerals can be scratched.

Measured by 10 easily recognized minerals developed by Friedrich mohs

6. Cleavage and Fracture Cleavage

Minerals that have cleavage will break in a certain direction where the bonds between atoms are not strong.

FractureMinerals that do not have cleavage will fracture when they are broken. If the fracture has a smooth curved

surface it is called a conchoidal fracture, otherwise most minerals fracture irregularly

7. Density and Specific Gravity Sometimes the same mineral may have

different weights which make different densities!

D = M/VDensity = mass / volume

Specific Gravity is a better and more accurate measure of density by comparing the ratio of the mass of a substance to the mass of an equal volume of water at 4* C.

http://www.rockhounds.com/rockshop/mineral_id/#Step4

http://facweb.bhc.edu/academics/science/harwoodr/Geol101/Labs/Minerals/Min10.htm

http://geology.csupomona.edu/alert/mineral/id1.htm http://www.glencoe.com/sec/science/lep_science/earth_science/tutor/content/pdf/masters/esg3_2.pdf

www.howtoteachscience.com/freestuff/worksheets/Mineral%20Properties%20Worksheet.doc