our kitchen was installed with black granite about a year ago. Granite looks as good as the day it was install.
Out granite length is about 30 feet long. The total length is still as shiny as it can be
Granite is no porous, i regular place hot pot directly on the granite and there is no marks

because stains overnight does not discolor the object or even items place on top of the counter for 1 year do not leave a stain.mark

marble is more porous, granite depending on type some are more porous than others

my toilet granites has not stain yet but this are black galaxy. I did use thiner to clean off some stubborn glass sealant and did not damage the granite

every 7 feet