Kudos to the Stoned Republicans of the High Frontier Panel and The Heritage Foundation for their groundbreaking earth shattering work on Smart Rocks!
[1] Brilliant Pebbles: https://en.wikipedia.org/wiki/Brilliant_Pebbles#Smart_Rocks
>In March 1988, Teller and Wood were able to directly brief President Reagan on the concept, taking the model pebble with them and theatrically hiding it under a black cloth when reporters were allowed to take pictures. Teller reiterated that the price for the system would be on the order of $10 billion.
Photographic proof (not AI generated): https://en.wikipedia.org/wiki/File:Brilliant_Pebbles_present...
[2] Pet Rock Remote Control: https://www.youtube.com/watch?v=SG0FAKkaisg
Featuring my Finger Flicking Pocket PC Pie Menus!
For those who don't understand I'd just point at the dietary habits of Discworld trolls.
Or something - "because I find it enjoyable" is a perfectly self contained reason as long as you aren't hurting anyone else (or yourself).
Unless you build a soundproof box for your rock tumbling - then you can run it 24/7.
I've also thrown a bunch into an aquarium as 'river stones', because it's illegal to take them from rivers here and buying them is way too expensive. Those are just bland, small pieces of dark granite to simulate the environment the aquarium is modeled after.