Rock Cycle Study GuideVocabulary Words

Rock Cycle – the process that recycles rocks into other kinds of rocks

Rock Key – a classification system for identifying unknown rocks

Igneous Rock – a rock that is created after lava or magma (melted rock) cools and hardens

Sedimentary Rock – a rock that forms when sediments press together

Metamorphic Rock – a rock that has been changed by heat or pressure

Hardness – the test of how easily one rock will scratch (or be scratched) by another object

Luster – the shine of a rock

Streak – the mark left by a rock when rubbed on a plate

Cleavage – the smooth break in a rock

Fracture – the rough break in a rock

Characteristics of Rocks

Igneous Metamorphic Sedimentary Forms when lava

(magma) cools and hardens

Can have crystals, air bubbles or a glassy surface

Most of the Earth’s crust is made up of this rock

Rocks that have been changed from heat and pressure

You can often see minerals in these rocks

Forms deep in the Earth

Formed when small pieces of rock are pressed together

You can often see fossils or other rocks in this rock

Often forms at the bottom of bodies of water

Igneous Metamorphic Sedimentary Granite

Pumice

Obsidian

Marble

Gneiss

Quartzite

Conglomerate

Sandstone

Coal

The Rock Cycle

Using The Rock Key

The rock key is a dichotomous key. What are some questions you can expect to see when using the rock key? What types of simple tools may be used?