Clastic rocks come in very different shapes and sizes, but they all have a few characteristics in common. A clast is a grain of sand, gravel, pebble, etc that makes up a rock. Clastic rocks look like they are made up of fragments of other rocks.


[am4show have=’p8;p9;p30;p57;p79;’ guest_error=’Guest error message’ user_error=’User error message’ ]


Materials


  • Small piece of plate glass
  • Magnifying lens
  • Vinegar
  • Paper towel
  • Shallow dish
  • Rock samples (in the video: bituminous coal, sandstone, siltstone, shale)


Metamorphic rocks are classified by as being foliated or non-foliated. Foliated rocks have layers, like bands around the rock. Non-foliated rocks don’t have any layers are are solid-looking throughout, although they might have crystals here and there. If the crystals are aligned to form a layer, then it’s a foliated rock.



Igneous rocks are classified as being extrusive or intrusive. An intrusive rock has a courser grain texture without a magnifier. Extrusive rocks need a magnifier to see the finer grains that make up the rock. Some extrusive rocks, like obsidian, need a microscope to see the fine grains.



Download worksheet and exercises


Clastic sedimentary rocks are fragments of other rocks. Geologists look at the tiny particle grains that make up the rock when they name the rock. For example, mudstone is named for its tiny particles of mud and clay, and sandstone is made up of larger grains of sand. The conglomerate rocks look like they are made up of pebbles. Siltstone under a strong magnifier show microscopic grains.


  1. Number and label your samples with your data table.
  2. Take your hand magnifier and look closely at each sample and record the color information on the data table.
  3. Use a dropper to take vinegar out of its bottle.
  4. Drop a few drops onto your sample and watch for a reaction. If you see a reaction, note this in the data table and classify the rock as a chemical rock, not a clastic rock.
  5. Wipe your samples dry with a clean, damp cloth.
  6. Test the hardness of your sample with the nail and record it in your data table using Mohs’ Hardness Scale.

Exercises


  1. Give three types of clastic sedimentary rocks.
  2. How can you tell a clastic from a non-clastic rock?
  3. Does hardness determine a clastic rock? If so, what hardness do you expect a clastic rock to have?

[/am4show]


Have a question ?

Tell us what you're thinking...

Comments

4 Responses to “Sedimentary, Metamorphic, and Igneous Rocks”

  1. Yes – look at pages 5-8 in the download. You should have pages for all three types of rocks.

  2. Robert D'Angelo says:

    Have you added the metamorphic and igneous lab worksheets yet?? I am still not able to find them. We are planning to do these labs today.

  3. Hi Doris,

    Yes the download for this experiment included lab worksheets for just the sedimentary rocks, but I noticed that one for metamorphic and igneous wasn’t included, so I will add in the additional content in the same download (you’ll need to download the file again to get the latest version, so check soon. Hope this helps!

  4. Doris Gatewood says:

    I see here the download only refers to sedimentary rocks, are there documents/charts for igneous and metamorphic?