Unusual substrate

[Specbaxter]

One more question guys. I have a friend who is a geology major and has a wide variety if naturally colored stones. I've been looking at this blue colored false emerald that naturally forms off the coast of Africa. It will take some research on the stones( I want to make sure that it will be safe for my set up) I was just wondering if anyone has heard of someone using natural stones that are not live and not normally found in an aquarium

 

[melosu58]

The only problem with that big stuff is that it gets food and waste trapped in it and then you start having excessive nutrient problems which lead to algea problems.

 

[Specbaxter]

It's not that big, it's called angelite and the Stuff I can get is what I would consider gravel sized