Mineral Identification Lab - Weebly



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:

• 12 unidentified Minerals

• Streak plate

• Nail

• 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

▪ Color

▪ Streak

▪ Cleavage/fracture

▪ Heft

▪ 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 12 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 |Streak plate-7 |

|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.

Density: D=M/V Where D=Density (g/mL), M=mass (g), and V=volume (mL)

Mineral identification Lab: Pre-lab worksheet Name:

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/Non-Metallic |Other Properties |Density | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |Mineral Name |Possible Colors |Streak |Hardness |Cleavage or

Fracture |HEFT

Light,

Medium,

Heavy |Luster

Metallic/Non-Metallic |Other Properties |Density | |Calcite |Clear to milky, orange, tan |White |3 |Cleavage |Light |Non-Metallic, glassy |Mineral takes a rhombic shape

Reacts with acid |2.72 | |Galena |Blue – black, grey |Grey-black |2.5 |Cleavage |Heavy |Metallic |Crystals maybe cut, very heavy |7.2 | |Graphite |Grey |Grey |1.2 |Cleavage |Light |Metallic | |2.16 | |Gypsum |Pinkish-white, white, grey, reddish-brown |White |1.5-2 scratches with fingernail |Cleaves |Light |Non-Metallic | |2.32 | |Halite |Clear, white |None |2.5 |Cleaves at right angles |Light |Non-Metallic |Tastes salty |2.16 | |Hematite |Black, grey, reddish-brown |Reddish-brown |5.5-6.5 |Fracture |Heavy |Metallic or rusty | |5.3 | |Hornblende |Dark –green, shiny bluish-black |Gray to white |5-6 |Cleaves into needlelike fragments |Light |Non-Metallic |crystals are needle shaped |3 | |Magnetite |Grey-black |Black |6 |Non cleavage, but octahedral parting |Heavy |Metallic |magnetic |5.15 | |Pyrite |Golden-brassy, yellow |Greenish black |6-6.5 |Fracture |Medium |Metallic | |5.02 | |Quartz |Clear, white, purple, rose, grey |None |7 |No cleavage, but conchoidal fracture |Light |Non-Metallic | |2.65 | |Sulfur |Yellow |White |1.5-2.5 |Fractures |Light |Non-Metallic |Smells like eggs |2.06 | |Talc |White, green |White |1 |Cleaves |Light |Glassy non-metallic |Powdery-greasy feel |2.75 | |

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