Download Mineral Identification Lab

Mineral Identification Lab
Introduction: In this lab activity you will become familiar with minerals and identifying
their different properties. This lab will also introduce you to the deductive process
where you will utilize the results of each property test to identify the name of the mineral
from an established key.
Materials:
 9 unidentified Minerals
 Streak plate
 Nail



File
Magnet
Penny
Procedure:
1. Place your name, date, class period, and bag number on your answer sheet.
2. Take all materials out of the bag and place them on your desk.
3. Go through and test each mineral for:

Hardness

Cleavage/fracture

Color

Heft

Streak

Luster
4. Be sure to record all information in the data table
YOU WILL NOT KNOW THE MINERAL NAME TILL
THE END OF THE LAB!!!
5. As your testing your minerals be sure to record your findings on your
record sheet
6. After you have tested all 9 minerals for all 6 properties, compare your test
results for each mineral to the established mineral chart in the back. Use
this chart to identify the mineral name.
Property Descriptions and Testing Procedures:
Color: This is probably the most easily observed property of minerals. However, color
often varies widely and is the least reliable property for identification.
Streak: The color of the mineral when powdered. To test for streak, draw the mineral
against an unglazed porcelain tile (streak plate). Streak is more useful for identification
than color is.
Hardness: A mineral’s hardness is it’s resistance to scratching. Mohs Scale of
Hardness, this scale uses common everyday objects to test hardness of each mineral
sample. Below is the resulting table.
Moh’s scale of Hardness
Rating Object used to test Hardness
1
2
Fingernail-2.5
3
Penny-3.5
4
Nail-4.5
5
Glass-5.5
6
Steel file-6.5
7
Streak plate-7
8
9
10
Cleavage or fracture: These two properties refer to the way in which a mineral breaks.
Cleavage is an orderly breakage in well-defined planes, meaning the mineral has flat
sides. Fracture is a random breakage. If a mineral breaks with rough, random surfaces,
it is said to have fracture.
Heft: Compare the relative “heft” of a mineral by holding it in your hand and comparing
it to other minerals of about the same size. In general, metallic minerals are heavier than
non-metallic minerals. For ease minerals are classified as 1.) light, 2.) heavy, 3.) very
heavy.
Luster: Refers to the way that a mineral reflects light. The simplest distinction is
between metallic luster (shiny and gold or silver color) and nonmetallic luster (does not
look like a metal in color, although it may be shiny). Particular types of nonmetallic
luster include pearly, vitreous (glassy), resinous (has the appearance of resin), silky, and
earthy (dull).
Other properties: Here are three additional tests that you should perform on all your
rocks. If you get a positive test, record it in your OTHER PROPERTIES COLUMN.

TASTE TEST: Certain Minerals have a particular taste. Two minerals halide and
quartz are very similar in appearance. One simple way to tell them apart is that
halide has a salty taste where as quartz has no taste.

SMELL TEST: Certain minerals give off a very distinct smell. Sulfur for
instance smells like rotten eggs

ACID TEST: You should test all your rocks to see if they will react with
hydrochloric acid. Place all your rocks on a paper towel and put a single drop on
each rock, one at a time. If you immediately see a vigorous fizzing in the drop, it
is calcite. Dry them a paper towel after you are done.

MAGNET TEST: if one of your rocks is attracted to a magnet, it may be
magnetite. But check all the other properties too because other iron ores are also
easily magnetized.
Mineral identification Lab: Pre-lab worksheet
Read through the lab handed out to you. Answer the following questions before you
begin your lab.
1. What are the 6 properties used to identify minerals
a.
b.
c.
d.
e.
f.
2. Briefly describe how you would test a mineral for each of these properties
a.
b.
c.
d.
e.
f.
3. What tool is used to determine the streak of a mineral?
Answer:___________
4. What is the name of the scale used to determine hardness?
Answer:___________
5. What is the difference between cleavage and fracture?
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
6. What are the two major categories of luster?
Answer:______________
Answer:______________
7. List the various descriptions for Non-Metallic Luster





Mineral
Name
Color
Streak
Hardness
Cleavage
or
Fracture
HEFT
Light,
Medium,
Heavy
Luster
Metallic/NonMetallic
Other
Properties
Mineral Name
Possible Colors
Streak
Hardness
HEFT
Light,
Medium,
Heavy
Luster
Metallic/NonMetallic
3.5-4
2.5-3
Cleavage
(how many
planes)
or
Fracture
Cleavage
Cleaves 1 plane
Azurite
Biotite
Blue
Brown
Blue
None
Light
Light
White
3
Cleavage
Light
Non-Metallic
Non-Metallic,
glassy, almost
translucent
Non-Metallic,
glassy
Calcite
Clear to milky,
orange, tan
Chalcopyrite
Brassy, Yellow,
reddish
Greenish-black
3.5-4
Fractures
Heavy
Metallic
Cinnabar
Red, purple,
Brownish-red
Red
2-2.5
Cleavage
Heavy
Non-Metallic
Feldspar
Gray, green
orange
Colorless
6
Light
Non-Metallic
Galena
Blue – black,
grey
Grey-black
2.5
Two planes of
cleavage that
meet at right
angles
Cleavage
Heavy
Metallic
Graphite
Grey
Grey
1.2
Cleavage
Light
Metallic
Gypsum
Pinkish-white,
white, grey,
reddish-brown
White
1.5-2 scratches
with fingernail
Cleaves
Light
Non-Metallic
Other
Properties
Very flexible
Mineral takes a
rhombic shape
Reacts with acid
Crystals maybe
cut, very heavy
Mineral Name
Possible Colors
Streak
Hardness
Halite
Clear, white
None
2.5
Hematite
Reddish-brown
5.5-6.5
Gray to white
5-6
Lepidolite
Black, grey,
reddish-brown
Dark –green,
shiny bluishblack
Pink, lilac
None
2.5-3
Magnetite
Grey-black
Black
6
Muscovite
Clear, white,
light brown
Colorless, light
brown
2-2.5
Pyrite
Greenish black
6-6.5
None
7
Sulfur
Golden-brassy,
yellow
Clear, white,
purple, rose,
grey
Yellow
White
Talc
White, green
White
Hornblende
Quartz
Cleavage
(how many
planes)
or
Fracture
Cleaves at right
angles
Fracture
HEFT
Light,
Medium,
Heavy
Luster
Metallic/NonMetallic
Other
Properties
Light
Non-Metallic
Tastes salty
Heavy
Metallic or rusty
Cleaves into
needlelike
fragments
Cleaves into 1
plane
Non cleavage,
but octahedral
parting
Cleaves in 1
plane
Light
Non-Metallic
Light
Non-Metallic
Heavy
Metallic
magnetic
Light
Non-Metallic,
glassy
Flat flexible
crystals
Fracture
Medium
Metallic
Light
Non-Metallic
1.5-2.5
No cleavage,
but conchoidal
fracture
Fractures
Light
Non-Metallic
Smells like eggs
1
Cleaves
Light
Glassy nonmetallic
Powdery-greasy
feel
crystals are
needle shaped