Intrusive igneous rocks are formed beneath earth’s surface from magma Are coarse grained, made up of large, visible crystals that grow together The larger the crystals are, the longer it took for the rock to form- beneath the surface temperature is higher and pressure will keep magma in liquid form

DIORITE USUALLY FOUND NEAR CRUSTAL PLATE BOUNDARIES AND INSIDE MOUNTAINS

GRANITE WHAT THE CONTINENTAL CRUST IS MAINLY MADE UP OF

Extrusive igneous rocks Form above the earth’s surface from lava Are very fine grained (have very small crystals that are visible) or they are glassy The smaller the crystals (or none seen at all) means the lava cooled very quickly

SCORIA VERY FINE GRAINED AND SHARP WITH VISIBLE AIR BUBBLES

BASALT ROCK THAT MAKES THE SEA FLOOR

PUMICE VERY VISIBLE AIR BUBBLES LOW DENSITY ALLOWS IT TO FLOAT

OBSIDIAN VOLCANIC GLASS

Is this intrusive or extrusive- how do you know?