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Identifying Rocks

This flowchart will help you to identify some common rocks.

By answering each question

and following the with the answer that best describes the rock you are trying to identify,

you will arrive at a possible name for the rock.

Not all rocks can be listed here, but the most common ones can be identified. Once you think you have identified your rock, click on the rock name to see a picture and detailed properties.

Start here

Look at your rock

Does it fizz with vinegar?


Marble
Metamorphic

What color are the crystals?


Granite
Igneous
Do you see many crystals in it?

How are the crystals arranged?


Gabbro
Igneous

Are all the layers the same?


Schist
Metamorphic


Gneiss
Metamorphic

Do you see sand grains or pebbles?

What size are the particles?

Small


Sandstone
Sedimentary

Large


Conglomerate
Sedimentary

Does it have holes or is it solid?

What color are the holes?


Tufa
Sedimentary


Scoria
Igneous
Pumice
Igneous

Does it fizz with vinegar?


Limestone
Sedimentary

Does it have a glassy surface?


Obsidian
Igneous

Does it have layers?


Rhyolite
Igneous
Basalt
Igneous

What type of surface does it have?


Slate
Metamorphic


Shale
Sedimentary