- the glass top can break if one is not careful;
- the glass can be scratched;
- the glass top can melt;
- the skillet can be prone to hot spots, producing uneven cooking; and
- the hot spots can cause damage to the skillet itself.
This topic has been discussed before on cooking.sx (perhaps this question should be cross-listed over there too?), but that thread didn't cite any sources and, well, I am a skeptic. Also, that thread did not address the possibility of damage to the skillet (claim #5 above).
I think claims 1 and 2 are reasonable given the coarse texture and heavy weight of some cast iron skillets, however, this answer seems to refute them. Claim 3 seems unlikely. Claims 4 and 5 seem to be open questions.
I'm interested because I used to live in an apartment with a glass-top electric range and I sometimes used a cast iron skillet on it. I was diligent about avoiding sliding any pots/pans on the surface of the glass, not only my cast iron skillet. The glass surface did develop some minor scratches on the surface, so I am wondering if that was due to my infrequent use of a cast iron skillet.
Are there any studies that document possible risks in using a cast-iron skillet on a glass-top electric range?