Limestone/flagstone

[losmetros]

I have some very nice pieces of flagstone and limestone. I know limestone is natural in South Texas, and was wondering if either of these rock can harm my new corns? I am going to sand them down and glue them together, but are the rocks toxic in anyway?
While i am here may aswell ask about my one new amel who has some wird looking scales. Right under her head the scales look a little greenish(only way i can explain it) and kinda crumpled up. Her atiitude is fine, and she just shed and ate, but I am just wondeirng about this. I was thinking about putting some cortisone on them, would this be ok to try?

[MegF.]

Both rocks should be just fine. I don't believe there is anything toxic in either of them. They do have rough surfaces however so make sure they are well secured and cannot fall onto your snake and watch to see that she isn't rubbing herself under them. I wouldn't try cortisone. Perhaps just cleaning it with some weak betadine or chlorhexidine would do. Keep it clean and see what happens after the next shed. She might have just rubbed it on something. If you don't see any improvement, or it worsens, you might have a vet check it to make sure it's not an underlying infection or fungus.