Rust on rocks?

[Jose]

I've had these rocks for a while. I took them out to put into my tank but it looks to have some brownish/reddish stuff on it. I'm not sure but I think it's rust. What do ya'll think? I uploaded pictures in my gallery.  http://houstonfishbox.com/modules.ph...g2_itemId=2580

Sorry for the bad pictures.

[Tiapan]

Re: Rust on rocks?

i cant see much from the pictures. but it is possibly just brown alge. try taking a hard brush to it. let me know if it comes off.

[Jose]

Re: Rust on rocks?

Sorry, it is petrified wood.

[alexrex20]

Re: Rust on rocks?

It's impossible for that shale to rust. It's just brown algae.