This EM carving technology is quite interesting. It seems that it was widely used in Atlantis times and probably for some period after its demise. The technology had to be scalable enough to be used on really fine objects like Egyptian vases made of very dense stone like granite with very high precision up to giant blocks and statues.
Independent researchers found a lot of evidence of stone machining in Egypt particularly made with rotary saws and tube drills. Though those marks suggested that instrument feed speed was so high, that no known to us instrument material could stand such strain and power required to operate such instruments would be immense.
The case of unfinished Aswan obelisk adds more details of this technology. The granite around the obelisk was removed with consistent scoop marks just like it was removed with an instrument capable of carving granite like raw clay though it's impossible to say exactly how "soft" was granite to those instruments.
Considering all this information and C's answers I can think of several ways this technology could operate:
- Stone was "evaporated" — the most unlikely one. No signs of extreme heating were found by researchers.
- Stone was temporarily "softened" — the most likely one. Scoop marks in Aswan quarry, trace metal (including titan) residues inside magnificent hard stone vases and enormous feed speed of tube drills support this hypothesis.
- Stone was "teleported away" — the most sci-fi one, but it couldn't be disregarded and could be used along with softening one. There are no actual evidence for this, but this way operator wouldn't need to do any machining — just get your "purse" and get the job done.
Few years ago I watched a really old (like VHS) video where some dude experimented with electromagnetic field generators and made items made from different materials like iron and wood "smelt" together without any visible thermal damage. It feels very similar to stone softening technology. (I can't remember the name of this guy, so I can't find the video, please drop a link if you do.)
I'm sorry I didn't ask a follow-up question right away to clear this up.