I just went camping and picked up a couple of rocks for my aquarium. They're granite, which I think is okay but I'm not 100% sure. I washed them off (of course) and I'm ready to put them in. Let me know so I can put 'em in Fluffy's house tonight!

Thnx,
Donna, Fluffy & the White Cloud Posse.

Hi dahnuh! I think your granite should be fine in the tank. It's an igneous rock, which are pretty stable, and it's composed of about 65% feldspar & about 25% quartz. There are some other constituents, mostly small amounts of muscovite & biotite micas & amphibole, which depending on your samples, could cause a problem in the way of flaking off. Most of the granite I've come across wouldn't create a problem for this reason. If your granite has a large amount of darker colors, or if it tends to 'flake'....I might hesitate if only for the reason of the fish eating the flakes, but granite is usually quite solid. I know I've read that granite is okay for the tank, but I also know that the feldspar minerals weather easily...this is in nature though, and I wonder if it would weather at all in a fish tank? Does anyone know anything about this aspect? Composition wise, you're fine, though.
Kristin

If I didn't know better, I'd think you were studying geology! The rock isn't flaky at all... it's the super-solid stuff that the Sierra Nevada mountains are made of. Thanks for your help, Gonzo. You're a dear!

No problem! I love to yap about rocks....yes I'm taking geology classes. I NEED to learn some more about shells & what not from watermama...hehe....Watermama....send me all you know!
Kristin

Hi there
Yah I think granite is ok - check out a post of mine......"will quartz be ok in my tank" - I cant remember who posted it, but they left a great link in there about what rocks are good and what rocks are EVVVVVVIILLLLLLLLL

http://www.uniquaria.com/articles/sr.html

Heres the link - hope it helps

Gee, thanks! Good link. I was very surprised to see sandstone in the "bad rock" list; they sell pretty multicolored sandstone in nearly every fish store I've ever been to.

Sandstone is something I've read is okay & not okay....I think it would be fine chemically b/c all it is really is quartz, but it would probably have the tendancy to break apart in the tank...or shed if you will. I have a huge piece of sandstone & thought about it for a second until I had to wipe all of the particles off my hands everytime I pick it up.
Kristin

BTW...I don't agree with putting porous lava rocks in the tank such as pumice or tuft. Maybe some do this for plants, and again they're chemically stable, but they're also FULL of lots of little holes & crevases. To each their own I suppose! Otherwise, that page sounds good to me!
Kristin

Gonzo, why are little holes and crevices bad?

I don't know? hehehe...I was thinking about hollow ornaments being bad...maybe they're not bad? Actually, MAYBE they'd be good for bacteria? What do you think?
Kristin

Lava rocks are good, I use to use them in my Cichlid tanks and they were good for breeding them, but as for goldfish I wouldnt use them cause of the sharp edges on them.

I never even thought about that Koko! Thanks!
Kristin

Tuft is smoother, isn't it?

Yup, I think tuft is a bit smoother. When I did my rock & mineral final, I remember having to study *extra* hard b/c I kept forgetting that the pyroclastic igneous rocks were defined as haxing a glassy texture....hehehe.
Kristin

so tuft might be a bit more friendly than lava rock. I'd hate to see my poor little oto scrape himself as he industriously works away at cleaning the tank. Fluffy avoids the rocks.