My+Rocks

Rock Families
 * There are three rock families:
 * #1 Igneous
 * #2 Sedimentary
 * #3 Metamorphic

Igneous rock forms from melted rock (lava or magma) when it cools
 * **#1 Igneous Rock** – “Born of Fire”


 * __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. **__Intrusive rock__** – igneous rock that is formed from cooled magma (e.g. granite)

2. **__Extrusive rock__** – igneous rock that is formed from cooled lava (e.g. pumice, basalt, rhyolite)


 * The main difference between intrusive and extrusive rock is their crystal size, which depends on how quickly they cool.
 * **__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__**