Determining Density

| Rock Collections| GNSC 320 Syllabus | Course Schedule |

The density of a mineral specimen is its mass or weight divided by its volume. It is usually expressed in grams per milliliter, or grams per cubic centimeter (1 cubic centimeter = 1 milliliter). A given mineral's density is constant, and does not depend on the size of the specimen.

Materials needed

• Mineral specimen that is not water soluble (don't try this with Halite!)
• Balance
• Graduated cylinder with a mouth wide enough to swallow the specimen

Procedure

1. Weigh the dry specimen on the balance. Your result will not be accurate if the specimen is wet (why not?). Record the weight in grams.
   • _________ g
2. Fill the graduated cyclinder about half full of water. Make sure the lowest level of the water (the meniscus) is right at an even volume (e.g., 30 ml). Record the water level in milliliters.
   • _________ ml
3. Drop the mineral specimen into the graduated cylinder. Careful! Try to slide it in gradually, so that it will not hit the bottom of the cylinder with a shock and shatter the cylinder. Also, your results will not be accurate if any of the water splashes out. Record the new water level in milliliters.
   • _________ ml
4. The volume of the mineral specimen is equal to the difference in water levels. Subtract step 2 from step 3.
   • _________ ml
   •  
5. Calculate the density in grams per milliliters by dividing step 1 by step 4.

• __________ g/ml