An old topic, but I thought I’d add a little to it.
tried a 59¢ gloss black ceramic tile from Lowes.
settings were full power, 400 speed, 225 lpi. 0.31 inch focus. paper application tape masking. Basic GF
after about 21 minutes, with the masking still on
after removing the masking. the contrast looks a lot better in the photo than actual. really just roughed it up with a very slight engrave.
took a cheap paint pen from Walmart, applied and then wiped off. I think it works fairly well. Will probably CNC a wood holder for it.