I. FormationThey are

formed when hot, liquid rock, or magma,

cools and solidifies (Hardens)

II. ClassificationIgneous rocks are classified

according to their composition and texture.

4 basic types of texturesGlassy – black and sharpFine grained – interlocking piecesCoarse grained – consist of

interlocking mineral crystalsPorphyritic – made of large crystals

scattered on the back of small crystals.

Igneous RocksCoarse-Grained

Fine-Grained

Granite

Gabbro Basalt

Rhyolite

III. Magma vs. Lava

Magma – molten material below the earth’s surface.

Lava – molten material above the earth’s surface.

MUST KNOW INFO

IV. 2 Types

of Igneous Rocks

A. Intrusive Igneous Rocks: Magma pushes into

surrounding rock below the Earth’s surface

Cools slower Large Crystals Think: (INSIDE)

Examples:

Did you know?!?! Granite is the most abundant intrusive

rock!

B. Extrusive Rocks: forms when

magma erupts onto the Earth’s surface (lava),

cools quickly very small or no

crystals formed Think:

(EXTERIOR)

Example:

Basalt is the most common

EXTRUSIVE igneous rock!

Did you know?!?! Another name for

an Extrusive rock is a

VOLCANICrock

A Closer Look at an Igneous Rock

Obsidian is a dark-colored volcanic glass that forms from the very rapid cooling of molten rock material. It cools so rapidly that crystals do not form.

Is it fine-grained or coarse-grained?

Is this rock Intrusive or Extrusive?

http://www.youtube.com/watch?v=PqgHUPSTojY

Igneous Rock Video

Must write down TWO things you learned!!!!

Be prepared to share!

http://www.youtube.com/watch?v=rkGVE6wNAzo

A little Science Rap