Rusty quartzite

[howmanyds]

I picked up 80 lbs of quartzite for my 75 gallon that I'm setting up from scratch. The stuff has been washed and scrubbed and is currently sitting in a bleach bath. Some of the pieces seem to be showing rust now that they've been drenched. Will this be a problem for African cichlids? There's also plenty of shiny flakes stuck to the rock. Maybe mica? Maybe quartz? Is this okay?

 

[okapizebra]

If it has rust then IMO I wouldn't risk it... metals can be toxic to your fish. However I don't know anything about that type of rock. If I were you, I'd play it safe and stick with something like slate.

 

[thomasina]

My daughter is a geologist and when I wanted to put mica in my tank cuz it is so pretty, she said no way! She advised me to do the vinegar test. When the stones/rock are dry, put about a tablespoon of vinegar on them. If the bubble, do not use them. I would be really worried if the are rusting! Anything in the Quartz family, from what I understand, is not the best. As okapizebra said, the have metal toxins. IMO go with slate. Safe and no risks!!