Yes you can score (engrave) Plaster of Paris (with settings & photos)

[rbtdanforth]

Found this:

So this happened.. (marble)

You created quicklime. Lasing hot enough you turned CaCO3 into CaO and CO2. CaO is highly reactive and grabs water out of the air and CaO + H2O → Ca(OH)2 that is Calcium hydroxide that pulls more water out of the air and of course is much more physical volume.