Quote Originally Posted by JSmith1983 View Post
The stone is slate backed and it is flat and you can't feel the pores. It almost has a shiny metallic look to it. wish I could get better pictures of it. It was sitting in a plastic tub that I keep alot of my other honing stuff in like stone holders and my other coticule and some other stuff. Most of the rest of my stones I keep in boxes. It didn't even dawn on me that my other coticule is a combo and was sitting on the top of this one for awhile and maybe with the BBW on top might have caused it. I thought coticules were non porous though. I was thinking maybe it was like some that will change color in sunlight. Thanks for all the info.
The vast majority are, to all intents and purposes, non-porous. However people who have made an extensive research of them (precious few) like Bart, formerly of Coticule.be, has identified at least two porous types, one only slightly porous, one more so.

Also on other coticule-worship sites like Artisan Shaving, there are examples of coticules getting stained. One I recall released something (or the razor that was being honed had a peculiar type of steel, or the water was acidic, or - something!) that resulted in copious rust-brown slurry that left the coticule stained - only lapping removed the stain.

Regards,
Neil