KYTL+5.2

Vocabulary

 * Extrusive rock**- a igneous rock that forms from lava
 * Intrusive rock**- a igneous rock that forms form magma
 * Porphyritic texture**- a rock with large crystals on a background of much smaller crystals

Characteristics of Igneous Rocks

 * Origin
 * extrusive rock- forms from lava
 * intrusive rock= forms from magma
 * intrusive rock forms beneath the surface
 * extrusive rock forms above the surface
 * basalt
 * forms much of crust
 * forms from lava
 * extrusive
 * granite
 * most abundant intrusive rock in continental crust
 * forms the core of many mountain ranges
 * Texture
 * texture depend on size/shape
 * fine-grained
 * lava cools rapidly (small crystals)
 * coarse-grained
 * slow cooling (large crystals)
 * porphyritic
 * forms when intrusive rocks cool in 2 stages
 * magma starts cooling (large crystals)
 * Mineral Composition
 * igneous rocks low in silica-dark colored
 * igneous rocks high in silica-light colored

Uses of Igneous Rocks

 * used for
 * tools
 * building material
 * statues
 * stonework
 * curbstones
 * floors
 * why?
 * hard
 * dense
 * durable
 * basalt
 * gravel for construction
 * pumice
 * cleaning and polishing
 * perlite
 * soil mixes