Other Types of Rock in Marine Aquariums?

[Hugh Mann]

I picked this up along with a bunch of other used aquarium equipment, and I am just wondering if anyone knows if it's safe to use in saltwater aquariums. By which I mean it won't leech silicates or other such things into the water and all that.

Neat little cave thing carved from rock. What type, no idea. dang it Jim, I'm a doctor* not a geologist!

*Not a real doctor.

 

[Reverend Turtle]

It looks to be one of the ceramic stones cichlid keepers use. If it is, it's perfectly safe.