Sedimentary Rock ID Lab

In this online lab, you'll be identifying twelve different sedimentary rock samples by their characteristics.
  1. Start by viewing the Introductory Video.
  2. Next, proceed to the Online Sedimentary Rock ID Lab.
  3. As you work through the lab, write your answers on the answer sheet.  Turn this in when you are finished.

  • The Hydrochloric Acid (HCl) test helps to identify whether the rock contains calcite and dolomite (these react with HCl).
  • Mineral hardness will only help you on those rocks made of one type of mineral!  (The lab won't let you use the test on the others.)
    • Gypsum has a hardness of 2.
    • Halite has a hardness of 2.5.
    • Calcite has a hardness of 3.
    • Dolomite has a hardness of 3.5 to 4.
    • Quartz has a hardness of 7.
      • NOTE: Gypsum has a hardness of two.  In this lab, a 2 will not scratch it, but a 3 will.  (The next higher number scratches it.)
  • Some of the rock names are used twice.  Some are not used at all.