Igneous rocks are formed from solidification of lava deposit
Examples are granite, basalt, obsidian
Sedimentary rocks are formed by the sedimentation and deposition of materials in the Earth's surface and the water.
Examples are shale, conglomerate, sandstone and limestone
Metamorphic rocks are formed as a result from a pre-existing rock (may be either an igneous or sedimentary). The original rock is subjected to such a high heat and temperature which affects the composition, silica content, and texture of the rock
Examples are quartz, marble(from sandstone), gneiss