Name Date Class

Igneous and Metamorphic Rocks

On a separate sheet of paper, compare and contrast how igneous rocks and metamorphicrocks are formed and classified.

Name Date Class

Igneous and Metamorphic Rocks

1. How are igneous rocks classified?2. Describe what a metamorphic rock is.3. Describe a situation in which heat can change rock to metamorphic

rock.4. Explain how the silica content of molten material affects the color of

igneous rocks.5. What characteristics do geologists use to classify metamorphic rocks?6. Describe one use each for the igneous rock granite and themetamorphic rock slate.

7. Igneous rock formed from lava that erupted onto Earth’s surface is called_________________ rock.

8. Igneous rock that formed when magma hardened beneath the surface of Earth iscalled _________________ rock.

9. _________________ describes the thin, flat layering found in most metamorphicrocks.

Understanding Main IdeasAnswer the following questions on a separate sheet of paper.

Building VocabularyFill in the blank to complete each statement.

Name Date Class

Igneous and Metamorphic Rocks

The Same But DifferentCan two different rocks with different names have the same mineral composition? the answer isyes. There are six major kinds of igneous rocks: granite, diorite, gabbro, rhyolite, andesite, and basalt.Geologists usually group these six kinds of igneous rocks in pairs, because each pair generally containsthe same minerals. Study the table below to see which igneous rocks are the same but different.

Common Igneous Rocks

Intrusive rocks(Coarse-grained)

Granite Diorite Gabbro

Extrusive rocks(Fine-grained)

Rhyolite Andesite Basalt

MineralsQuartz, Feldspar,Muscovite,Amphibole

Amphibole,Feldspar, Pyroxene

Feldspar, Pyroxene,Olivine, Amphibole

Color Light colored Medium gray orgreen

Dark gray to black

Silica content of rock decreases

Rock color becomes darker

  1. Which of the six major kinds of rock are intrusive and which areextrusive?

  2. Compare granite with rhyolite. How are they similar? How are theydifferent?

  3. Compare the mineral composition of diorite with the mineralcomposition of andesite.

  4. In what way is gabbro different from basalt? What can you inferfrom this about how these two kinds of igneous rocks form?

  5. How is granite like gabbro?  6. Which rock has more silica in it, granite or basalt?  7. Is a rock with more silica in it more likely to be lighter or darker than

a rock with less silica in it?

It’s possible for a single mixture of minerals to produce more than one type of rock. Readthe passage and study the table below. Then use a separate sheet of paper to answerthe questions that follow.

Name Date Class

Igneous and Metamorphic RocksIf the statement is true, write true. If the statement is false, change the underlined wordor words to make the statement true.

  1. _________________ Any rock formed when another rock is changed by heat orpressure is a metamorphic rock.

  2. _________________ Geologists classify metamorphic rocks according to the size ofthe grains making up the rocks.

  3. _________________ Extrusive rock forms beneath Earth’s surface.

  4. _________________ Metamorphic rocks are unfoliated if their mineral grains arearranged in parallel layers or bands.

  5. _________________ Igneous rocks are classified by their origin, texture, and mineralcomposition.

  6. _________________ Extrusive rocks have larger grains than intrusive rocks.

Write the letter of the correct answer on the line at the left.

7. ___ Which terms best describe igneousrocks?

A light and easily broken

B soft and smooth

C hard and dense

D soft and dense

9. ___ Which metamorphic rock has an evengrain and can be cut into thin slabs or easilycarved?

A marble

B basalt

C granite

D slate

8. ___ Which igneous rock is used forcobblestones and landscaping?

A marble

B basalt

C granite

D slate

10. ___ How do coarse-grained igneousrocks form?

A from sedimentary rocks changed underpressure

B from large rock particles cementedtogether

C from rapidly cooling lava

D from slowly cooling magma