National Geographic Rock Tumbler Kit

A rock tumbler is a small barrel that spins rough stones in grit for days until they come out glossy, and the National Geographic kit is the one that works out of the box: a quiet motor, a pound of rough gemstones, four grades of grit, and a guide that explains what is happening. The first batch takes about a week and the wait is part of it.

It is the Christmas gift for a son or daughter around eight to twelve who collects rocks from every parking lot, and the gift grandparents buy because they want to run it with the kids. It is a project, not a toy, which is why it is remembered.

It runs in a garage or a laundry room since it hums. Refill grit and stones are cheap. Under sixty dollars for a gift that produces something a kid made.