Welcome and great to see enthusiasm!
Perfect opportunity to research the physical properties of granite and carbon based composite materials. You'll need to find out about density, vibration, rigidity and the ways these physical properties apply to the mechanical aspects of mechanical motion based machines. Look at the forces applied in 3 dimensions (or more) and how to addresses those. How to move mass around (and stop it).
Other experienced builder folks here can chime in and provide some feedback.
Great project with a practical goal/application in mind.
Good luck!