Sedimentary Rock:

Definition: These rocks often start as sediments carried in rivers and deposited in lakes and oceans. When buried, the sediments lose water and become cemented to form rock and form very slowly over time.

Examples: Common sedimentary rocks include sandstone, limestone, and shale. 

Metamorphic Rock:

Definition: Metamorphic rock is a rock that has been changed from its original form by intense heat and pressure very slowly over time to a new form. 

Examples: Examples of metamorphic rocks include marble, slate, gneiss, quartzite, schist, soapstone, and phyllite. 

Igneous Rock:

Definition: Igneous rocks “fire-born,” meaning that they are formed when magma or lava cools and solidifies. They can form relatively quickly or even almost immediately. 

Examples: Examples include scoria, pumice, tuff, basalt, diorite, diabase, granite, and gabbro.

Pyroclastic:

Definition: Composed chiefly of rock fragments of explosive origin, especially those associated with explosive volcanic eruptions. 

Examples: Volcanic ash, obsidian, and pumice are examples of pyroclastic materials.