Janai Otero
Gregory Mathis
4.04 Identifying Rocks Worksheet
Igneous Rocks:
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 Igneous rocks are formed when lava cools underground. They are also
formed when volcanoes erupts causing the magma to rise to the top of the
earth’s surface.
 The specific name for the rock formed when lava cool and hardens below
the earth’s surface is an extrusive and intrusive igneous rock.
The crystal size compare in extrusive vs. intrusive rock have different process. For
intrusive rock are characterized by large crystal size, well their appearance shows
individual crystals interlocked together to form the mass. Extrusive rocks are
formed from magma at or above the surface of the earth, and normally display
smaller minerals crystals or no crystals at all, because of cooling environment in
which they form. The obvious difference between the two are the crystal size,
intrusive rocks have a large crystal/grain texture due to slow cooling of magma
below the earth surface which boots the growth of large crystals, while extrusive
rocks, because of the fast cooling at/ above the earth’s surface does the opposite.
Intrusive rocks are formed inside the earth. Extrusive rocks cool from lava and are
formed outside of the earth.
Sedimentary Rocks:
 Sedimentary rocks are formed when sediments is stashed out of air, ice,
wind, gravity, or water flow carrying the particles in termination.
 The name of an impression formed when tiny plans or animals become
trapped between sediment layers become a cast.
 Three examples or sedimentary rocks: Some sedimentary rocks are formed
from bits of other rocks. Some are formed from bits that were once part of
living things. Another way that sedimentary rocks are formed is from
minerals that dissolve in water. Over time, after the water evaporates, just
the mineral crystals are left behind as sediment.
Metamorphic Rocks:
 Metamorphic rocks are formed when sedimentary, igneous, or another
metamorphic rock are physically deformed and chemically changed due to
different temperatures and pressure.
 Igneous and sedimentary rocks become metamorphic rock as a result of
intense heat from magma and pressure from tectonic shifting. Although the
rock becomes extremely hot and under a great deal of pressure it does not
melt.
 Limestone: Over time, after the water evaporates, just the mineral crystals
are left behind as sediment.
 Sandstone: Sandstone is a very soft sedimentary rock that breaks easily.
When you break a piece off, you can feel the grains of sand that make up
sandstone.
 Shale: Shale is actually composed of mud and clay that has collected
underwater.
 Granite: It is an intrusive rock, meaning that it crystallized from magma that
cooled far below the earth's surface.
Sample Foliation
Intrusive/
Extrusive
Fossils
Texture
Metamorphic/
Sedimentary/
Igneous
Name of Rock
Example
No
Extrusive
No
Coarse
Igneous
Diorite
1
No
Intrusive
No
Coarse
Granite
Diorite
2
No
Extrusive
No
Fine
Basalt
3
Yes
Intrusive
No
Coarse
Gneiss
4
No
N/A
Yes
Nongrained
Limestone