There are 3 major types of rocks…
Intrusive- created inside the earth (in magma)
Extrusive- Created outside the earth (in lava)
Clastic- Fragments of other rocks form together
Chemical- Form from minerals combining with chemicals or evaporates
Foliated- bands of chemicals form
Non-foliated- no real pattern of minerals
Igneous Rocks are first to form. Igneous means from fire because these rocks form in magma.
Sedimentary are the rocks that form over time from pressure when pieces of other rocks break off.
Metamorphic rocks are rocks that get buried and form from heat and pressure but do not Melt- they just reform into new and different rocks.
Determining the type of rock is dependant on several different things….
1 - If you can see clear mineral deposits, it is probably igneous
Large- probably intrusive and small- probably extrusive
2- If it appears to have pieces of rock combining to form it is probably sedimentary
3- If it appears to have layers, it is probably metamorphic