How crude life must have been, we may think, when there was no metal. But stone is a worthy servant. In fact, stone tools have been found that are more than 2 million years old. And stone tools are still around. I don't mean stone used for construction, but things you can hold in your hand and do stuff with.
Stones are great for grinding.
One stone tool that's still in common kitchen use is the mortar and pestle, better than anything for turning things to a powder or paste. And maybe you seek out stoneground flour for your baking needs. Perhaps the highest use of stone today along these lines is in the tough, heavy granite rollers used for conching chocolate . And let's not forget chalk, the soft stone used for writing on blackboards or sidewalks. But what makes me light up is edged stone tools.