granite stain

Dear Sir,
My name is Chris Oberle. I have a nasty stain problem
on a granite floor in my bathroom. The toilet was
leaking from the wax seal. You can see where this is
going. It was a slow leak so it appeared little by
little. Last night I fixed the leak, but it left a
stain around the outside of the base of the toilet
that's about 1 in thick. Its dark, looks like a water
stain, but it hasn't dried after 24 hours. Most of the
leakage was water, but it was mixed with the black
fungus that grows in the wax ring. Gross huh? Sorry.
Will a hydrogen peroxide poultice work?
Thank you kindly!
Chris.