Download 7th Grade Science

What is igneous rock?
• Any rock that forms
from magma or lava
• Classified by origin,
texture, and mineral
composition
• EX: (your
experience, new
question, or WU
answered.)
Origin: what is extrusive?
• Extrusive: formed
from lava that
erupted onto the
Earth’s surface.
• Basalt most
common extrusive
rock.
• EX: (your experience, new
question, or WU
answered.)
Origin: what is intrusive?
• Intrusive: formed
when magma
hardened beneath
the earth’s surface.
• Granite is the most
common intrusive
rock.
• EX: (your experience, new
question, or WU
answered.)
What determines texture?
• Rapidly cooled lava =
fine-grained igneous
rock with small crystals
• Slow cooled magma =
coarse-grained igneous
rock with large crystals
• EX: (your experience, new
question, or WU
answered.)
What is the most common
mineral of the Earth?
• Most of Earth’s
minerals contain
silica.
EX: (your experience, new
question, or WU answered.)
• Why does Mrs.
Clark have a picture
of sand?
How does the mineral composition (silica)
affect the color of igneous rocks?
• The silica content of
magma and lava
affects the types of
rock they form
• less silica = dark
colored rocks
• More silica = light
colored rocks
More silica or less silica?
What is igneous rock used for?
• Tools, building materials, art
Egyptians
3,500 years age
Incas of Peru
600 years ago
Mt Rushmore
National Memorial.
South Dakota, USA
180 years ago