I was asked if I could engrave text on a small gold plate. Has anyone here tried it?
A quick Duck search for “laser reflectivity of gold” returns a huge number of sources. All of them suggest reflection efficiency of ninety-five percent or higher.
This would indicate that you stand a good chance of damaging something in the light path, probably starting with the lens. In normal use, the lens collects a broad beam and focuses it to as near a point as possible. Reflecting nearly all that energy back into the lens may not be well advised.
I think the general rule is you can’t ‘do’ metal with these lasers. Meaning cuts and most engraving. Some of the ‘big’ heavy co2 they do use on metal but they are commercial and expensive.
Most metals have a high reflectivity rate. Aluminum molecule is something like 99.6% reflective in a wide range of frequencies.
There are a few ways to coat the metal then use the laser to molecularly fuse the material in the coating to the metal. I use
But there are many others. It’s non toxic and washes off and I think it’s ok for septic systems…
Of course it leaves a black ‘mark’…
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I’m well aware of the fine reflective properties of gold (and copper for that matter), but hoped someone could “jump forward” and say I’ve done this and that. Until now, I have not worked with color spray and all the special recipes to be able to engrave metals, nor do I have the right time and desire for this kind of experiment right now.
There is also no way to buy a fiber laser, I have no space left in my workshop and my otherwise quite positive wife will not think it’s fun anymore. 
But thanks for the links and the interesting feedback.