My+Rocks

Rock Families There are 3 rock families:
 * 1) Igneous ( fire rocks)
 * 2) Sedimentary ( water rocks)
 * 3) Metamorphic ( changed rocks)

Igneous rock-“born of fire” Igneous rocks forms from melted rock (lava or magma) when it cools. Lava- Melted rock that is found outside (“on”) the Earth’s Crust. Magma- Melted rock that is found inside the Earth’s Crust. When lava and magma cool, they form two different kinds of Igneous rock:


 * 1) In trusive rock- Igneous rock that is formed from cooled magma (example Granite)
 * 1) Ex trusive rock- Igneous rock that is formed from cooled lava (example Pumice,basalt and rhyolite)



Extrusive rock- (from lava ) cools quickly and forms small crystals.

Intrusive rock- (from magma ) cools very slowly inside the Earth’s Crust and forms large crystals.
 * __ Sedimentary Rock __**


 * 1) 2 Sedimentary Rock – (“Layer’s of rock”) – “Nature’s Cement”


 * __sedimentary rock__** – rock that is made from __sediments__ that usually form in layers.


 * __sediments__** – loose materials such as sand, mud, and gravel (and plant and animal remains – fossils)

As these layers of sediment slowly pile on top of each other, they become tightly packed or cemented together to from rock


 * These sediments are moved by water, wind, and gravity and settle on top of each other in layers (called __beds__).


 * These beds push on the layers below and create enough pressure to form sedimentary rock – **__compaction__**

Or, as dripping water coats the sediment with dissolved minerals and cements the pieces together – **__cementation__**


 * __E.g. mudstone (shale), sandstone, limestone, and conglomerate__**

Metamorphic Rock Metam orph ic Rock- “changing form” Once a rock exists (as igneous or sedimentary) it can be changed into another, different kind of rock by using pressure and heat (and lot of time). Rock that has changed into a new type of rock. The original rock (parent rock) is changed by pressure and heat to form a new metamorphic rock. Examples Granite- turns into Gneiss. Sandstone- turns into Quartzite. Mudstone- turns into Slate. Limestone- turns into Marble.