Question

How does a pebble become smooth and shiny?

Answer 1

erosion by water , air and other causes

or man made causes like sanding it using sandpaper and polishing it

Answer 2

These pebbles form as the flowing water washes over rock particles on the bottom and along the shores of the river. ... Because river current is gentler than the ocean waves, river pebbles areusually not as smooth as beach pebbles.

I hope this is a right answer