Will this slate be safe??

[KarlosFandango]

Bought some chunks of slate for the new tank. I've broken one up and there are some really strong veins of iron?? running through it. Will what ever it is affect fish?

Picture here

Karl

 

[Joviella]

I wouldn't use it......it could affect your water quality. Just my opinion, maybe others will disagree.

 

[The-Wolf]

No it won't be safe, the iron will break down over time and add unwanted chemicals into your tank. By the way that is not slate, it's shale.

EDIT
see this Topic.