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Minerals Properties Lab Display Stations (old)

Luster

Mineral name Chemical formula Sample
pyrite FeS2
 
 
 
 
 
 
 
 
chalcedony SiO2
 

   
 
 
 
 
 
limonite Fe2O3 · H2O
 
 
 
 
 
 
 
 
  1. Describe the luster of each sample.
  2. Which two of these have a nonmetallic luster?


 

Color

Mineral name Chemical formula Sample
azurite Cu2(CO3)2(OH)2
 
 
 
 
 
 
 
 
fluorite CaF2
 
 
 
 
 
 
 
 
amphibole CaNaMg4Fe3Si6O22(OH)2
 
 
 
 
 
 
 
 
  1. Describe the color of each sample.
  2. Looking at these samples, make a prediction about the color of minerals containing copper.
  3. Why isn't color a reliable identifier of minerals?




 

Streak

Mineral name Chemical formula Sample
pyrite FeS2
 
 
 
 
 
 
 
 
specular hematite Fe2O3
 
 
 
 
 
 
 
 

  1. Describe the streak color of each sample.
  2. What is surprising about the color of one of these streaks?




 

Cleavage / Fracture

Mineral name Chemical formula Sample
muscovite KAl3Si3O10(OH)2
 
 
 
 
 
 
 
 
quartz SiO2
 
 
 
 
 
 
 
 
calcite CaCO3
 
 
 
 
 
 
 
 

Do not break these minerals - look at evidence of how they have broken in the past.
  1. Does the sample mineral exhibit cleavage or fracture?
  2. Does table salt exhibit cleavage or fracture?




 

Heft

Mineral name Chemical formula Heavier or lighter?
halite NaCl
 
 
 
 
 
 
 
 
galena PbS
 
 
 
 
 
 
 
 

Rather than measure the actual specific gravity of the mineral samples, we will gauge the 'heft' or the relative weight of the samples.

  1. Which sample is heavier?
  2. How would looking at the chemical formula help you answer heavier or lighter?
  3. Does halite exhibit cleavage or fracture?






 

Crystal Form

Mineral name Chemical formula Sample
goethite HFeO2
 
 
 
 
 
 
 
 
malachite Cu2CO3(OH)2
 
 
 
 
 
 
 
 

  1. Does the sample mineral exhibit a regular (repeating pattern) or irregular crystalline shape?
  2. Does halite have a regular or irregular crystalline form?




 

Hardness

Mineral name Chemical formula Sample
mineral a Al2O3
 
 
 
 
 
 
 
 
mineral b Mg3Si4O10(OH)2
 
 
 
 
 
 
 
 
mineral c CaF2
 
 
 
 
 
 
 
 

Procedure:

  1. With only these three tools to use you will only be able to give a range of Mohs hardness. i.e. " mineral A is between 2.5 and 3.5
  2. See if the mineral first scratches your fingernail. If it doesn't it must be softer than....
  3. If it scratches the penny then it must be harder than...
  4. If it scratches glass then it must be harder than...
  5. Describe the range of Mohs Hardness numbers of each sample.

Wow:   Mineral 'a' is used to make sandpaper and in a pure form is also called a ruby!

 

Special Properties

Mineral name Chemical formula Sample
magnetite FexOy
 
 
 
 
 
 
 
 
sulfur S
 
 
 
 
 
 
 
 
  1. Describe a special property of each sample.
  2. Why are there variables (x and y) in the chemical formula for magnetite?
  3. What other minerals in this lab might have the same special property as magnetite?
  4. Why do you think this?