[greenbirds]

Or something else?? I bought a bunch of this rock assuming it was slate.. Now I'm not so sure. While rinsing and scrubbing it clean, I noticed that some pieces continued to release a fine, clay-like mud as I scrubbed. Other pieces that look identical, however, seemed solid and rinsed clean. These rocks are not crumbly or sharp, but some do have some very fine, shiny particles adhering to some surfaces, with no shiny stuff on the edges. Many of the rocks are very flat on one side and somewhat textured/pitted on the other (as in the 4th photo).

I just started the bucket test to see if an oily residue results from a soaking.

 

[mavericks]

It looks like flagstone to me. Oklahoma silver mist or Pennsylvania blue grey.

 

[greenbirds]

Thank you for that. I looked at some photos of the silver mist flagstone and mine appears to be very similar. Any chance you know if it actually contains any silver (bad for fish)? Google searches have been no help. Many sites talk about "silver and gray colors" but make no mention as to whether it actually contains any.

 

[mavericks]

I think that silver just refers to the overall color tone. I've only used it on pools...but I can't imagine it being harmful to fish.

 

[mavericks]

Sorry...it just came to me! I have a buddy who used silver mist in a Koi pond.