The Rock Cycle

The ________ cycle is a model of how all rocks can be formed, transformed, destroyed and reformed depending on the environment and processess that affect them. A rock can transform into any other rock without following a particular _____________ .

The texture of a rock and its mineralogy is the best way to determine its origin:

1. ________________ rocks are composed of sediments (rock fragments) from weathered rocks or ____________ matter cemented into layers. Most of the time these sediments are readily visible and you can see how they are __________________ together! Rocks made by chemical ______________ from evaporating water are composed of soft intergrown crystals. (For instance on cave ceilings!) If a rock has a ______________ in it, it's a sedimentary rock!

2. _______________ rocks form when magma or lava cools. In most cases you can SEE the coarse intergrown crystals (like puzzle pieces). Rapid cooling, however, can make the crystals so small that you can't see them (fine texture) or they don't exist (__________ texture). Sometimes gas bubbles get hardened inside the rock making it look frothy (vesicular).

3. Metamorphic rocks are also composed of intergrown crystals, but they show layering, banding or foliation (the layered _____________ of flat crystals). Often the layers look bent or distorted. _____________ and pressure form a metamorphic rock.