Steve Igneous

r

-melted rock (minerals) called magma-can come from volcanoes-can be under the ocean-near tectonic plate edges

extrusive

often dark

small crystals

cools quickly

"holey"

came from a volcanoe or large cracks

called lava when on the surface

obsidian - volcanic glass

Ryolite

no acid reaction

no layering

several minerals

plate seperation ridges

Intrusive

course or large crystals

cool slowly

hardens under the earths surface

Granite

gabbro

no fossils

magma

volcanoes

under the ocean or on the surface