Rocks!
Engraving rocks
I found some beautiful flat and smooth rocks from beaches of Reykjavik and Reynisfjara black beach and I thought it would be nice to try some engraving on them. I first checked the fabwiki pages to see if someone had done some testing with rocks and found out that marble settings were good to start with. I googled the settings and found a page with some standard settings for 35W lasercutter so I decided to try their settings first.
The settings were speed 75, power 80, DPI 600.