I only just got my glowforge setup yesterday so I’m not exactly an expert in it’s settings yet. I have to say that it’s the quickest machine from unboxing to actually doing something with it of all the 3D printers and mills that I’ve spent money on. I am very happy!
There has been some discussion in the boards on engraving various unusual things like semi-precious stones. A friend of mine cuts opal and was very curious about the possibility of engraving designs or just figures over flaws in the stone. So one of the first experiments I had to run on it was trying to engrave some opal!
It’s mentioned several times on this forum that opal has too much water as a part of the matrix and that it would just blow apart or crack. Thats always a danger with Opal and if your settings are too high then I have no doubt that you could crack or craze or destroy it, but my initial testing turned out very nice. I’m not happy with the resolution but it actually looks quite nice.
I took an unpolished piece of sub gem quality, white matrix, opal with a very flat face and attempted to place my initials on it. These are 2 passes at 35% power. The stone is actually etched, not just discolored. I can clearly feel that it’s etched slightly into the stone and not just discolored it. I think it would look quite nice if done more artistically than I can do with just burning in my initials.
There are issues of course. I don’t believe you would have any hope to actually cut opal with this laser. I don’t know what it would do to a truly gem quality piece, or if this one was very dried out, or if the curve of a nicely polished piece would give it trouble. So don’t do this to a multi-thousand dollar gemstone quality piece without a lot more experimentation. But I know there are those here who would love to see the picture.