Transcript Why Is It So Difficult to Identify Minerals?

 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!
 1. Color: _____________________________________
 2. Luster: ________________________________
 3. Streak: __________________________________
 4. Texture: __________________________________
 5. Hardness: ________________________________
 6. Cleavage/Fracture: ___________________________
 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!
 The way that a mineral reflects light from its surface is its luster
 The two types of luster are:
- metallic
- nonmetallic
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 color
 For 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.
 Texture describes how a mineral feels to the touch.
 Minerals can range anywhere between glassy feeling, rough feeling, greasy
feeling, and even soapy feeling!
Talc has a soapy texture.
Fluorite has a
glassy texture.
Hardness
 Hardness is a
measure of
how easily a
mineral can
be scratched
 Geologists
use Mohs
scale to give
minerals
their
hardness
ratings
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 break
 Cleavage: 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
 Some minerals have unique properties
 For example, Iceland spar can create double images
 Calcite reacts with hydrochloric acid and releases carbon dioxide
(bubbles)

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!
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4. Read pages 40-48 in “earth’s surface” books and answer questions 1-6 on one piece of paper. Late!
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5. Lab #1 : Pick up paper and materials for lab 1- follow instructions on paper
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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
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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)
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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