ROCK KEY

1a. If the rock is made up of minerals that you can see, go to 2a.

If not, go to lb.

1b. If the rock isn't made up of visible minerals, go to 5a.

2a. If the rock is made up of minerals that are interlocking (melting together) go to 3a.

If not, go to 2b.

2b. If the rock is made up of minerals that are noninterlocking, go to 6a.

3a. If the minerals in the sample are of the same kind, the rock is metamorphic.

If not, go to 3b.

3b. If the minerals, in the sample are of two or more different types, go to 4a.

4a. If the minerals in the sample are distributed in a random pattern (not lined up), the rock is igneous.

If not, go to 4b.

4b. If the minerals in the sample are not distributed randomly but show a preferred arrangement or banding (lined up), the rock is metamorphic.

5a. If the rock is either glassy or frothy (has small holes), it is igneous.

If not, go to 5b.

5b. If the rock is made up of flat sheet that look as though they will split off into pieces, it is metamorphic.

6a. If the rock is made of silt, sand, or pebbles cemented together (it may have fossils), it is sedimentary.

If not, go to 6b.

6b. If the rock is not made of silt, sand, or pebbles but contains a substance that fizzles when dilute hydrochloric acid is poured on it, it is sedimentary.

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