Three Major Types of Rocks  Igneous  Sedimentary  Metamorphic

 Igneous  Latin word meaning,“fire.”  Forms when magma or molten rock, cools or hardens.  When magma hardens and is exposed on the Earth’s surface, its called lava.

 Sedimentary  Erosion causes these rocks to form  Wind,waves, ice, water break down all rocks types into fragments known as sediments.  These sediments are compressed or cemented together.

 Metamorphic  Certain forces and processes  including pressure, extreme heat and chemical process change the form of the existing rock to a new form.  Changed form

Rock Cycle  Any of the three of the major types of rocks can be changed into another of the three types.  Geologic forces cause to change and form into new rocks. This process is called the Rock Cycle.  Rocks on Earth’s crust undergo this cycle many times.  National Geographic Explorer (Student Magazine) - Quick Flicks National Geographic Explorer (Student Magazine) - Quick Flicks

Properties of Rocks  All rocks have physical and chemical properties.  The way a rock weathers or break down, is based on the rocks chemical stability of the mineral in the rock.

Bowen’s reaction Series  In early 1900’s a geologist named N.L.Bowen began studying minerals crystallizing from magma.  He learned that as magma cools, certain minerals tend to crystallize first.  He came up with Bowen’s reaction series.  Which is a flow chart showing the order in which mineral form when magma solidifies.

Chemical Stability of Minerals  This is the measure of the tendency of a chemical compound to maintain its original chemical composition rather than break down to form another mineral.

Physical Stability of Minerals  How physically stable a rock is.  Rocks breaking, due to zones of weakness.  Zones of weakness are called joints.