Slate-is it safe??

[Buddy09]

OK, I have used slate in tanks before and currently, as it's readily available here, at least the standard grey stuff. I found out that a local supplier has different colors, green, purple, even red on hand....I am assuming that the different color are due to different mineral contents in the slate, but I'm no geologist so I'm guessing....Does anybody know what the difference is and more importantly does it MATTER?? As long as it won't leach toxic minerals/metals into my tanks or change the ph it should be fine, but I'm always leery of sticking unknown things in my tanks.

[2wheelsx2]

It's actually due mainly to the different oxidation states during the mud deposition and then the subsequent metamorphism during which mudstones are turned into slates. They may be some minor carbonates, but for the most part, slates are fairly tight and carbonate free. What you do have to watch for is if there is abundant metallic minerals like pyrite etc, but I'm sure you'd recognize it as such (metallic minerals, not the specific one).

Slate is one of the safest rocks to use in a tank mineralogically.

[Buddy09]

Works for me 2wheels...I like slate in general because you can get it in fairly thin, flat pieces that work well for caves and such without adding huge amounts of weight to your tank. Also it's pretty easy to cut with a power saw and a cheap $2 masonry blade, at least the thinner stuff. Found the colored stuff today and thought it might add a bit of pizzaz over the generic grey stuff I typically use....thanks for the input.

[2wheelsx2]

They should be able to be "cleaved" pretty easily too, if you score the surface first. Slate is pretty brittle.