Igneous Rocks are classified according to their
origin, texture, and mineral composition.
A rock that is formed from the cooling of molten
rock. It is either magma below the surface or lava
above the surface.
ORIGIN:
EXTRUSIVE ROCK
INTRUSIVE ROCK
Rock that is formed
Rock that is formed inside
Outside
Ex. Basalt
Ex. Granite (light in color)
(Dark in color)
TEXTURE
FINE-GRAINED
Glassy texture
LARGE GRAINED
large grain (coarse)
IGNEOUS rocks form from “Red- Hot” and fiery
molten material.
What is the most common type of intrusive rock?
Granite.
What is the most common type of extrusive rock?
Basalt
Explain how the silica content of molten material
affects the color of igneous rocks? Lava that is low in
silica usually forms dark-colored rocks. Magma that
is high in silica usually forms light-colored rock.