On 25 Oct, 01:50, Robatoy wrote:
Did you know you can stain granite if you forget to seal it?

In principle from empirical reports yes, but with my geologist's hat
on I can't think how you manage to do this. Granite is (or ought to
be) pretty tough stuff - impervious mineral grains that are closely
bonded without any sort of pervious matrix. Barring the odd mechanical
fissure, just how do you "stain" granite? What happens here - do the
grains change colour, or does some visible stain get absorbed into the
material? Which granites (chemically) are prone to it? What
substances will cause staining?