1. Rocks and rock cycle

2. A rock is a NATURALLY OCCURRING, COHERENT (i. e
A rock is a NATURALLY OCCURRING, COHERENT (i.e. not a pile of loose materials) SOLID material,
consisting of:
ONE OR MORE MINERALS, or,
GLASS (e.g. obsidian), or,
ORGANIC MATTER (e.g. coal)

3. Metamorphic rocks Sedimentary rocks
Erodes
Becomes
That weathers
Deposits and lithifies,
Exposed to:
Increased pressure
High heat
Hot fluid
Any existing rock
Becomes
Photos by Prajukti Bhattacharyya
Mississippi Delta image courtesy Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison and the MODIS science team (source: accessed August 20, 2014) is freely available for re-use
under these terms:
That melts
Which cools to make
Sedimentary rocks
Becomes magma
Igneous rocks

4. Igneous rocks
Form when magma becomes solid
Form either by cementing broken pieces of pre-existing rocks together (e.g. sandstone), or,
by precipitation of minerals out of water solution (e.g. limestone)
Sedimentary rocks
Form when pre-existing rocks are altered by heat and/or pressure and/or hot fluids into new rocks without becoming anything else in between.
Metamorphic rocks