Rocks Suitable For Freshwater Aquariums

[damanax]

to start with, Slate is a no go as I can't find it in town.
 
What other kinds of rock would work in a freshwater setup?
 
I've recently changed my tank over from sand but the bottom still looks a little bare to me and I'm debating between adding some more wood, some rocks or some dried leaves.
 
Current fish are 1x Angelfish, 2 x Platy, 12 Rummynose Tetra, 7 Albino Cories.
 
Thanks!

 

[simplyfish]

This is a link from another site I've seen.
 
I've been looking at the same thing recently.
 
http/www.cichlid-forum.com/articles/rock_metals.php