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

Metallic Nonmetallic 2. Luster Shiny Not shiny Reflects 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.

Fracture Minerals 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/V Density = 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/#Ste p4 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/eart h_science/tutor/content/pdf/masters/esg3_2.pdf www.howtoteachscience.com/freestuff/worksheets/Miner al%20Properties%20Worksheet.doc