Please help me ID these rocks

[freshcichlid]

I think mine looks like the left pic of Colen's.
In my pics, they are of the same rock, just both sides

 

[colen]

In the pinned topic about rocks it says sand stone is not recommned. I wonder if they are safe or not, they both have the same texture and feel the same.

 

[colen]

In the pinned topic about rocks it says sand stone is not recommned. I wonder if they are safe or not, they both have the same texture and feel the same.

 

[3fsh]

The right one is definitely slate and I *think* the left one is too, but I'm only 95% sure. There are two things you can do, aside from the vinegar test. Bash a small corner of it with a hammer... if it crumbles off, it is definitely not slate. If it breaks off cleanly or into several flat pieces then I'm 99% sure it's slate. Also, test the pH of some tap water and then add the rock to it. Let it sit for about a week and then test the pH again. If the pH doesn't go anywhere, I'm betting it's slate. Hope that helps.

 

[freshcichlid]

haha thats too much work, ill just go to the rock quarry and ask for slate. but thanks for info, im sure it helped a lot of other people out
ps - 3fsh ill get that stuff in the mail soon ive just been swamped with things, sorry ! and if you havent sent the fish you can wait too, im havin a problem with my tank and the ammonia/nitrates ! i dont want to kill my new little guys

 

[colen]

I guess I have taken bad pictures of these rocks as I am positive neither are slate. Thank you all for the help though it is greatly appreciated.

Saturday I am going out to purchase rocks I can ID and know that are safe for my tank as I am worried to use these ones.