Geochemistry Question:

Minerals or small particles of rocks, become rocks through pressure and temperature, often deep inside the earth’s core, or simply through pressure for instance on the seabed.
Wherever many small things become something big it is usually through compression, temperature, or pressure.
The opposite process – large things being worn into smaller particles – usually comes through another sort of force. Either weathering, erosion – action by wind, rain, and water – is responsible.
Gradually many rocks are eroded by movement of ice and water over them or the wind action also to become finer and finer and form little grains – e.g. of sand or of soil.