Rock ID Test
Rio Hondo Prep School

 

Welcome to the Rock ID Test. You will be presented a series of photos with accompanying descriptions...it is your job to select the correct answer.

When attempting to determine what kind of rock you are looking at, it is often easier to first to determine how the rock formed..or in other words, what major rock class does the rock belong to. From there, you should be able to determine the rock name. If you can't determine the main rock type, you probably can't determine the rock name.

There are three main classes of rocks as shown in the table below. Each of those classes are split up into sub categories. Review the table below and then we'll proceed with a few examples.

Igneous (New rock formed from melted rock) Sedimentary (Rocks made of pieces of pre-existing material Metamorphic (Pre-existing rock changed by heat and/or pressure
Intrusive Extrusive Clastic Chemical Biochemical Foliated Non-foliated
Magma cooled underground slowly, forming interlocking crystals Lava cooled quickly on the Earth's surface; no visible crystals Rocks made of bits and pieces of weathered and eroded rock. Rocks formed by the crystallization of chemicals, generally accumulating in lakes which dry up, causing crystallization. Rocks formed from parts or chemicals from dead things, usually composed of silica (shell parts) or from carbon (from plants). Rocks which flake or cleave in layers. Generally formed under intense pressure which aligns the minerals into layers. Do not have platy or sheet-like structure. Formed by heat but not pressure in most cases.
Granite Basalt Sandstone Limestone Coal Slate Quartzite
Diorite Rhyolite Breccia Evaporites Chert Gneiss Marble

 

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Rio Hondo Prep School
Physical Science

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