So here's the story, It seems like there are many conflicting opinions on what rocks are "safe for aquarium". in the research I've done it seems that rocks that dissolve in acid (bicarbonates) and tht can be etched with a stainless steel knife are bad. However, what if a rock is just able to be...

In the Mt. Tam area they have this pretty green rock that is serpentine rock. Someone told me not to use it in my aquarium because it has high levels of arsenic. Does anyone know whether this is a problem; will it leach out?