What Kind of Rock Is This?
ES0610  Homogeneous-Looking Rocks

  !   Read the questions below each image. If your answer to the question is yes, click the blue text to go to the next step to identify the rock.

Try to scratch the surface with a nail. Does the nail scratch the rock or does the rock scratch the nail?

If the rock is harder than a nail, your rock is probably quartzite. Note that some quartzite still shows bedding planes from when it was a sedimentary rock.

Is the rock softer than a nail? Go to chemical test.
When viewed through a hand lens or magnifying glass, does the rock contain small, non-interlocking crystals?
Is the rock dark colored?
Matthew Nyman, TERC

If you have identified your sample, return to the beginning of the rock identification key, select another rock sample, and begin the process over again.

If your rock sample does not have any of the features described on this page, reexamine the rock with a hand lens or magnifying glass. Look at the sample from all angles. Concentrate on fresh surfaces where you might be able to better determine the texture. Return to the beginning of the rock identification key and start over again.