Colored pencils or
highlighters needed:
Orange, LIGHT blue,
pink, LIGHT green,
yellow Rock Exploration of the ESRT
Igneous
Name
Period
Date
1. On the diagram below, color the whole column “Crystal Size” orange from top to bottom. Color
the column “Texture” yellow from top to bottom.
2. In terms of crystal size, what does fine refer to?
And Coarse?
3. On the diagram above, lightly color the intrusive rocks pink and the extrusive rocks light green.
4. Compare the crystal sizes of the intrusive igneous rocks with the extrusive igneous rocks.
5. Extrusive means the rock formed above the Earth’s surface-from lava that cooled quickly.
Intrusive means the rock formed below the Earth’s surface-from magma that cooled slowly. How
does the rate of cooling affect the crystal sizes of the minerals within the rock?
6. Glassy is a term that means non-crystalline. This does NOT mean shiny. Both rocks pictured below
are glassy. Did these rocks form above or below the surface?
7. One of the rocks pictured above is vesicular. The other is non-vesicular. Label them!
8. What does vesicular mean?
9. On the diagram below, color the 5 vesicular rocks yellow.
10. Are these rocks extrusive or intrusive?
11. Which of the vesicular rocks cooled fastest?
12. Below are pictures of 2 non-vesicular rocks. One is intrusive and the other is extrusive. Label
them and then justify your answer.
13. The slower the magma cools, the _______________ the mineral crystal size.
14. The more time it takes for the magma to cool, the ____________ the magma cooled.
15. Are RATE and TIME the same thing? Explain.
Use this chart to answer questions 16- 22.
16. Where the rock names are placed on the chart is dependent on three criteria: Color, density, and
composition. You will find these three criteria along the arrows at the bottom of this chart. Felsic
and mafic are two terms that are used to describe the composition of the rock. Felsic means the
rock is rich in silica and aluminum whereas a mafic rock is one rich in iron and magnesium. Circle
the terms mafic and felsic on the chart above.
17. Highlight the 6 light colored rocks.
18. If a rock is light colored, what can you infer about the composition of the rock?
19. If a rock has a lower density, what can you infer about the composition of the rock?
20. If obsidian usually appears black but is placed on this left side of the chart, what can you infer
about its composition?
21. Name a rock that is light colored, vesicular AND glassy.
22. Name a mafic, fine grained, non-vesicular rock.