The rocks are getting very smooth, but they don't show a nice sheen yet. Maybe after the polishing stage they'll look nicer.
Stage 3 - 500 Grit

Stage 3 is one week tumbling the rocks in 500 grit.
This is the last smoothing stage before the polishing stage.
The rocks lost weight again.

Some of the pretty ones look good.

Add beads to bring the weight back up and keep the rocks from chipping.

Move on to Stage 4