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
