Sealer for sandstone heads and cills.

Hello there, i am ready to plaster my house. I have sandstone cills and sandstone heads showing right around my house. I was wondering has anyone got them in their own house and if so have you come across a sealer to seal them with, i.e to stop fungi etc!!! also i'm looking to darken them down a bit!

Many thanks.

sinno12, i would be grateful if you could let me know where you purchased your cills from please

check mcmonagle stone ,donegal, web site they have a stone sealer that might do your job