Saw cut marks on a pillar at the Pantheon in Rome that the tour guide never pointed out
I was in Rome two weeks ago and did the normal tourist stuff, but the one moment that stuck with me was at the Pantheon. While everyone was staring up at the dome, I noticed these thin horizontal lines cut into one of the big granite pillars near the entrance. They looked like tool marks, maybe from when the stone was first shaped or maybe from later repair work, and I stood there for a good ten minutes trying to figure out which. I took about 15 photos and zoomed in later, and the marks show a repeating pattern that looks like a chisel edge about the width of my thumb. A guard walked by and I asked him about it, and he just shrugged and said most people never look at the columns at all. I get that the dome is the star, but it surprised me how much is sitting right at eye level that nobody mentions. Has anyone else spotted tool marks or old repair scars on famous monuments that the guides skip over? I would love to know what those lines actually are, because my best guess is ancient quarry marks but I am not sure.
Those horizontal lines on the Pantheon columns are almost certainly ancient quarry or finishing marks, and the good news is you don't need a guide to read them. Next time bring a small flashlight, hold it at a low angle to the stone, and the chisel pattern will show up way more clearly than in photos. The guards usually won't know the answer, but the site guides or a good book on Roman building tech will.