Classifying Rocks

Geologists classify sedimentary rocks into three major groups: _______ rock, chemical rock, and organic rock.

clastic

Rocks that have large grains you can easily see are described as _____ grained

course

The way in which each of the three major groups of rocks forms is _________

different

Color alone ______ provide enough information to identify a rock.

does not

A rocks _______ give the rock it's texture.

grains

Magma that is ____ in silica usually forms light-colored rocks, such as granite.

high

Any rock formed when another rock is changed by heat or ________ is a metamorphic rock.

pressure

The deeper a rock is buried, the greater ________ on that rock

pressure

Quartzite forms when quartz particles in _________ recrystallize.

sandstone

Heat and pressure change the rock _____ into slate.

shale

Because the foliated metamorphic rock ______ splits apart easily into flat pieces, it is used for roofing materials.

slate

Extrusive rocks have _____ grains than intrusive rocks.

smaller

Marble is often used in sculpture because its even ______ allows it to be carved into complex and detailed shapes.

texture

_________ rock forms beneath Earth's surface.

Intrusive

Which generally describes granite?

Light-colored rock with high silica content.

What sedimentary rock (formed from coral, shells, and skeletons that buried up on the floor) is this?

Limestone

Which is a kind of rock that forms when heat or pressure change an existing rock?

Metamorphic

Geologists classify metamorphic tocks according to the ____________ of the grains making up rocks.

arrangement

Rocks that are _______ have grains that lie in a pattern of flat layers or form swirls.

banded

Metamorphic rock ___ form out of other metamorphic rock.

can

Which forms when minerals dissolved in a water solution crystallize?

chemical rock

Which term describes how a rocks's surface looks and feels?

Texture

How many rock-forming minerals make up most of the rocks of Earths crust?

20

_______ is used for cobblestones and landscaping.

Basalt

What rock is formed from the remains of swamp plants buried in water.

Coal

What is the process by which sediments get pressed together?

Compaction

Which term describes igneous rocks?

Hard and dense

Sand grains, pebbles, mud, shells, and leaves are all examples of __________.

Sediment

Clastic rocks are grouped by the ________ of the rock fragments of which they are made.

Size

How do coarse-grained igneous rocks form?

Slowly cooling magma.

The metamorphic rock ______ usually forms when limestone is subjected to heat and pressure deep beneath the surface.

marble

Metamorphic rocks are _______ if their mineral grains are arranged randomly

nonfoliated

Igneous rocks are classified by their _____, texture, and mineral composition

origin

People throughout history have used igneous rock for _____ and building materials.

tools

Which is the process that breaks up rock on Earth's surface.

weathering