There are over 3000 types of minerals in the Earth’s crust

As you could see with the quartz, often times even the same kind of minerals can look very different

Therefore, geologists (scientists who study minerals and rocks) often use several different tests to determine type of a mineral they have found!

Why Is It So Difficult to Identify Minerals?

1. Color: _____________________________________2. Luster: ________________________________3. Streak: __________________________________4. Texture: __________________________________5. Hardness: ________________________________6. Cleavage/Fracture: ___________________________

6 ways to identify a mineral

Color is one of the most noticeable characteristics of a mineral, but it also the least reliable of all the characteristics

The color of a mineral is often caused by tiny amounts of other elements or compounds inside

For example, what people call amethyst is actually just quartz with iron in it!

Color

The way that a mineral reflects light from its surface is its luster

The two types of luster are:- metallic- nonmetallic

Luster

Metallic Luster

When a mineral is rubbed against a tile, it will leave behind a colored powdered streak on the tile

Sometimes a mineral’s streak does not match the mineral’s external colorFor example, one way

to tell the difference between pyrite (Fool’s gold) and real gold is by streak. Pyrite leaves a greenish-black streak while real gold leaves a yellow streak.

Streak

Texture describes how a mineral feels to the touch.

Minerals can range anywhere between glassy feeling, rough feeling, greasy feeling, and even soapy feeling!

Texture

Talc has a soapy texture.

Fluorite has a glassy texture.

Hardness is a measure of how easily a mineral can be scratched

Geologists use Mohs scale to give minerals their hardness ratings

Hardness: Books p. 36Hardness Mineral Associations and Uses

1 Talc Talcum powder.

2 Gypsum Plaster of paris. Gypsum is formed when seawater evaporates from the Earth’s surface.

3 Calcite Limestone and most shells contain calcite.

4 Fluorite Fluorine in fluorite prevents tooth decay.

5 Apatite When you are hungry you have a big "appetite".

6 Orthoclase Orthoclase is a feldspar, and in German, "feld" means "field".

7 Quartz  

8 Topaz The November birthstone. Emerald and aquamarine are varieties of beryl with a hardness of 8.

9 Corundum Sapphire and ruby are varieties of corundum. Twice as hard as topaz.

10 Diamond Used in jewelry and cutting tools. Four times as hard as corundum.

The pattern of atoms will determine how a mineral will breakCleavage: A mineral that breaks relatively easily and evenly at

angles (smooth)

Fracture: Minerals that break with rough or jagged edges are said to have fracture

Cleavage and Fracture

Some minerals have unique propertiesFor example, Iceland spar can create double images

Calcite reacts with hydrochloric acid and releases carbon dioxide (bubbles)

Some Other Special Properties

1. Research: go to my google classroom and work on assignment: What is a geologist? Late!

2. Finish conclusion of boat lab answering these questions under your materials list: (science notebooks): Late! Was your hypothesis correct/ incorrect? Why do you think this is? Could any other variables have affected your results? Why/why not? And which variables?

3. Finish p. 6 of your bread lab (research 3 sources on info about mold growing on bread) (packet) Late!

4. Read pages 40-48 in “earth’s surface” books and answer questions 1-6 on one piece of paper. Late!

5. Lab #1 : Pick up paper and materials for lab 1- follow instructions on paper

6. Lab # 2: Big book- issues and earth science, lab paper, materials Part 1 (front of worksheet): p. B8 – B10

Blank paper: analysis on blank paper from p. B10 Part 2 (back of worksheet): p. B12 - B13

Blank paper: under work from p. B10, answer analysis on p. B12- B13

Turn all materials, lab paper and analysis papers into black bin 7. Computer: pick up “mineral mania” paper. Go to google classroom and

follow directions to fill out 8. Review worksheet 9. Lab# 3 – Assessment grade!! Big Books- issues and earth science p. B 21

– B 24 (Don’t choose properties that are the same for calcite & quartz) After your fill out p. 1-2 of worksheet, come pick up materials you chose to test

your mineral

10. Computer: Go on google classroom and complete assignment titled “Mineral Letter Home” based off your findings from lab # 3