LPKW+5.2

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=5.2 Igneous Rocks=

Vocabulary

 * extrusive rock**-rock that hardens on the earths surface
 * intrusive rock**-rock that hardens below the earths surface
 * porphyritic texture**-a rock with large crystals scattered in a bakground of much smaller crystals

Outline

 * Igneous rocks**
 * Characteristics of Igneous rock
 * Origin
 * Geologists classify rocks by where they were formed
 * Texture
 * The texture of a igneous rock can vary depending on the size and shape of mineral crystals
 * the size of crystal depend on how the rock cooled
 * Mineral Composition
 * The silica content of magma and lava affects how easily magma or lava will flow
 * Uses of Igneous Rocks
 * Ignoeus rocks has been widly used for tools and building materials