ROCKS

By Prof. Liwayway Memije-Cruz

ROCKS•Rocks are made up of

two or more minerals•They are NOT crystal•Rocks are collections

or aggregates of one or more mineral.

Rocks are classified into:•Igneous Rock•Sedimentary Rock•Metamorphic Rock

•

IGNEOUS ROCK It is the rock formed by the

solidification of molten magma.

Are formed from the molten liquid minerals that lie below the earth’s crust.

Most abundant type of rock

Two categories of Igneous RockPlutonic or Intrusive: Characterized by large crystal sizes. They cool slowly deep in Earth’s crust. Ex. (granite, gabbro and diorite)

Volcanic or Extrusive:it comes from lava.fine grained and quickly cooled.Ex.(basalt, obsidian and pumice)

SEDIMENTARY ROCK

• These sediments are moved by wind, water, ice or gravity.

• Sedimentary rocks represent 7% of the Earth’s crust, but they cover 70% of the Earth’s surface

METAMORPHIC ROCK Rocks that have

changed due to intense temperature and pressure

Meta” means “ change ” and morphosis means “ form ” in Greek

Igneous, sedimentary and other metamorphic rocks can change to become metamorphic rocks.

Gneiss, a common type of metamorphic rock