UNDER CERTAIN CONDITIONS, HOT ROCKS OF THE UPPER MANTLE AND LOWER CRUST MELT FORMING A MOLTEN LIQUID CALLED MAGMA. IGNEOUS ROCKS FORM WHEN MAGMA SOLIDIFIES.

* SIZE, SHAPE AND ARRANGEMENT OF MINERAL GRAINS , OR CRYSTALS.

1.) VOLCANIC

2.) PLUTONIC

*THESE TYPE OF ROCKS FORM AS A RESULT OF MAGMA SPEWING OUT ON TO THE EARTHS SURFACE. THE LAVA THEN COOLS AND SOLIDIFIES.* THESE ROCKS ARE FAST COOLING AND AS A RESULT HAVE SMALL OR NO CRYSTALS

* “GLASS” COOLED FAST UNDER WATER. THERE ARE NO CRYSTALS!!

* GASSES BLAST FROM A VOLCANO AND SOLIDIFY, BUT LEAVE MANY AIR BUBBLES IN THE ROCK.

* THIS TYPE OF ROCK IS FORMED WHEN MAGMA SOLIDIFIES WITHIN THE EARTH’S CRUST. * THE OVERLYING ROCK INSULATES THE MAGMA LIKE A THICK BLANKET.

* MAGMA CRYSTALIZES VERY SSSLLLOOOWWWLLLYYY!!

* CRYSTALS GROW OVER HUNDREDS OF THROUSANDS TO MILLIONS OF YEARS.

GRANITE IS THE MOST ABUNDANT ROCK IN THE CONT. CRUST

* WHEN A ROCK IS FELSIC, IT MEANS IT HAS MORE ALUMINUM THAN OTHER STUFF. (Al)* LOWER DENSITIES

EX: GRANITE, RHYOLITE, PUMICE

* HAVE LIGHT COLORS*

* LOCATED ON THE RIGHT SIDE OF “IGNEOUS ROCK IDEN. CHART. (P.6)

*DARKER IN COLOR* HIGHER DENSITIES

* MORE IRON(Fe) AND MAGNESIUM(Mg)

PUMICE

BASALTRHYOLITE

GRANITEGABBRO

OBSIDIAN

* INCREASED HEAT AND PRESSURE UNDERGROUND CREATE THESE ROCKS

CHARACTARISTICS-DO NOT MELT

-MAY SHOW CRYSTALS IN BANDS-SOMETIMES LOOK LIKE CRYSTALS HAVE MELDED OR SQUISHED TOGETHER

-MAY LOOK DISTORTED

* THIS USED TO BE SHALE

*THIS USED TO BE CLAY OR FELDSPAR

* THIS USED TO BE GRANITE

*THIS USED TO BE LIMESTONE!!