A collection of laser engraved, 4 inch slate tile microchip coasters.
More info: https://www.evilgeniuslabs.org/macrochips
I have a Flux3D Beamo 30W CO2 laser. I use the metal engraving preset (50% power, 80mm/s speed).
A light coat of mineral oil before engraving makes them shiny, if that's the look you want.
For custom designed, laser engraved items such as these, contact me here: https://www.evilgeniuslabs.org/contact