How to tell if moulding is lime or plaster of paris

[jfwibberley]

Hi,

I've stripped the paint off of some decorative moundings in a early 1900's house. But I need to repaint it with a suitable primer / paint. But I can't tell whether it is lime or plaster of Paris, is there any way of telling? I've attached some images.

Thanks,

Josh

 

[stuy]

White wine vinegar onto lime will fizzle

 

[BryanJ]

From past experience.
If it was run in-situ, (made in place on the wall) then the finishing coat could be 50,% lime and 50% plaster.
Cast out of a mould ( made on a bench) and fitted more likely to be 100% plaster.
Looking at the photo, the corbel was cast and the quirk bead on the arch was run in-situ.