Rock (Ore? Is that rust?)

[Dragonwolf]

Hi all. I got a rock from the person I bought my tank from and I hadn't put it in the tank because it has reddish brown spots on it and I wasn't sure if it was rust. Any rock "experts" able to help me out here. Took a few pictures, 2 with flash and 2 without. If anyone has any ideas on whether it would be safe to put in or not, please let me know.

Thanks!

 

[Convict2161]

Hi all. I got a rock from the person I bought my tank from and I hadn't put it in the tank because it has reddish brown spots on it and I wasn't sure if it was rust. Any rock "experts" able to help me out here. Took a few pictures, 2 with flash and 2 without. If anyone has any ideas on whether it would be safe to put in or not, please let me know.

Thanks!

Have you tried to clean it and brush it off? It may come off. Also either way I'd soak it in very hot hot water for a little.

 

[Rivercats]

First take a couple drops of vinegar and drip onto the rock to see if it bubbles or sizzles. If so that means it can raise the Kh, Gh, Ph in your tank. Also IMO any rock that contains ore of any kind shouldn't be used in an aquarium as it will leach metals many of which can be toxic to fish if high enough levels are reached.

 

[Dragonwolf]

Well it passed the vinegar test. Nothing happened to the vinegar whatsoever. The drops just sat there without sizzling or bubbling.

 

[Dragonwolf]

I just remembered I have some strong ball bearing type magnets... and there is a slight attraction between the magnet and the rock. I'm not going to put that in my aquarium.

 

[jcolon]

Yes that's Iron staining, it's an igneous rock of some sort probably rich in iron.