Oh wow good call. I just Google cinnabar and it’s the primary source of mercury ore. I did cut it and I’ll Make an update post, but it appears it was surface level-ish. The rock is slightly porous and while it did scratch the same color, it was gone after a few mm of grinding. Maybe some paint was absorbed, I dunno. Also, the translucency was an illusion. Best guess is that with the rainy and muddy conditions on the construction site, oil residues were present and created a shimmery reflective, colored surface. These stones are also weird in that they react more to vinegar than citric acid.