The Earth

Goal: Identifying Rocks

Materials and tools

Obtain at least 10 different rocks for identification.
Rock identification guide.
Vinegar
Old piece of tile

Procedure

Select your rocks and be prepared to explain your selection methodology and what you could accomplish with it. For example, you could collect similar rocks from different locations or different rocks from the same location. If you don't have access to a good outside source, you can use a sampler selection from the local science/education toy story.
Examine each rock and determine whether it was metamorphic, igneous, or sedimentary in origin. What criteria did you use?
Place a small amount of vinegar on the rock. Does it fizz, indicating the presence of calcium oxides?
Try to scratch the back of the tile with the rock. Does the rock scratch the tile, or "shed" on the tile? A rock that scratches the tile is harder than one that is itself broken down by scraping along the rough tile back. [For more information on the Scratch Test, read the the Streak Test for Minerals page at the Geoscience News and Information site.]

Report

Instructions

Describe the source for your rocks; if you got them by collecting them outdoors, identify the location and its geology.
Make a table and list the rocks, a brief description, your general identification (igneous, sedimentary, metamorphic), and a specific identification where you were able to make it.
If you were able to visit a natural area, describe your analysis of its geological history.

Resources

The igneous rock classification site at California State University at Pomona has a wonderful graphic of the classification system used by the International Union of Geological Scientists when identifying rocks of suspected igneous origin. Why are standards required for classification?

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