1. Igneous Rocks Sample Pictures of Different Igneous Rocks and their Textures

2. Course Grained Granite- Formed from the slow cooling of magma. Large crystals form.

3. Uses of Granite Granite is used for long lasting monuments and for trim and decoration on buildings.

4. Fine Grained Rhyolite- Formed from the rapid cooling of magma. Very small crystals.

5. Uses of Rhyolite Rhyolite is used as an Rhyolite is used as an aggrigate.

6. Porphyritic Rhyolite Porphyry- formed from unequal or mixed cooling of lava. Larger crystals on a background of smaller crystals

7. Porphyritic Granite porphyry- formed from unequal or mixed cooling of lava. Larger crystals on a background of smaller crystals

8. Glassy Texture Obsidian-result of instantaneous cooling of the lava.

9. Vesicular Pumice-full of tiny holes due to gas bubbles that were trapped inside when the lava cooled.

10. Uses of Pumice Because it is so light, pumice is often used as a decorative stone in gardens. When ground up into a powder, Pumice is used as an abrasive in polishing compounds. Pumice is also found in Lava soap.

11. Intrusive vs. Extrusive Intrusive Igneous Rocks- Form on the inside of the earth’s crust from magma. Typically have larger crystals due to the slower rate of cooling. Extrusive Igneous Rocks- Form on the earth’s surface from lava. Typically have smaller crystals due to the more rapid rate of cooling.