The recycling machine works something like this. Liquid (molten) rock material solidifies either at or below the surface of the earth to form igneous rocks . Uplifting occurs forming mountains made of rock. The exposure of rocks to weathering and erosion at the earth's surface breaks them down into smaller grains producing soil. The grains (soil) are transported by wind, water and gravity and eventually deposited as sediments. This process is referred to as erosion.

The sediments are deposited in layers and become compacted and cemented (lithified) forming sedimentary rocks. Variation in temperature, pressure, and/or the chemistry of the rock can cause chemical and/or physical changes in igneous and sedimentary rocks to form metamorphic rocks. When exposed to higher temperatures, metamorphic rocks (or any other rock type for that matter) may be partially melted resulting in the creation once again of igneous rocks starting the cycle all over again.