CHoffman

Hey guys,
So I put all the rocks in the 125 mbuna tank and now I'm noticing when they are wet they have sparkle in it..Kinda like you would see in fools gold but just here and there. I'm wondering if this has any adverse effect on water quality.

kojen

i think i would wait and do a water test after a little while. it could just be a mineral deposit that will never affect your tank. some of my rocks have what looks like lines through them that sparkle and i have never had a problem with them

prairielilly

Can you post a pic? like REALLY close up? might be able to identify and tell you whether or not it's inert.

mathas

Without knowing what is giving your rocks the sparkle, it's hard to say. If it is pyrite, you would not want that in an African cichlid tank. Cichlid-forum has a good article that explains the chemistry:

http://www.cichlid-forum.com/articles/rock_metals.php

CHoffman

I tried to get a pic but my camera is acting up....I'll get it working and post a pic...I appreciate your help guys..
Thanks for the link Mathas. Very interesting. I'm going to check the pH to see if it has lowered the it or not. That will give me a indication whether it's pyrite or not.

CHoffman

Did a PH test it was 8 which is what my tap is so the rock isn't lowering the ph...IS there some kind of test I can do to test water?

prairielilly

The link from mathas is good. I don't know that I could identify a rock from a photo anyway (we usually use at least 10X magnification lol) but a pic would still help.

Might be able to help a bit if you can describe the rock: colour? can you see any obvious linear features, if so are they parallel? Is it irridescent like glitter or sparkly like glass? Rounded edges, or sharp? can you see lots of little grains in it? does it have holes? Where did it come from specifically? where are you located geographically, are there any major features near you (mountains, desert)?

Sorry for the interrogation, in all likelihood it's just fine except if it's got copper-containing minerals in it or something that will leach, which is what I'd like to rule out.

CHoffman

Here is a pic of the rocks in my tank..(still can't get my camera to work)..This was taken just to show what I had done so it's not a close up of the rocks but you can get a idea on what they look like. YOu can click on the pics and zoom in not much but it helps. Pics of my 125 with rock Some people are using this rock to side their new house they are building and building a fence with it. We got a ton of it for free. It's more like glitter. It's very small and sprinkled throughout the rocks. We are from Kansas but that doesn't say anything about the rock because it was brought in for the new house. I did notice a hazy film on top of my water today. There are no fish in there but I think to be safe I'm going to pull them out and get different rock. They were free so were not out any money. But allot of work.

prairielilly

Oh that helped a lot! (looks really nice btw). I can't say for certain but I could narrow it down to a few possibilities, both of which unfortunately are commonly used to clad buildings/houses:

- sandstone. In this case the 'glittery' stuff is likely quartz (silica), which is inert (no worry!) The orangey dusty stuff might be a concern as that could be iron oxide (chemical equivalent of rust). Not sure? I know ppl add ferts with iron when they have plants but we also use water conditioners to remove/neutralize iron, someone else may be able to advise there.

- limestone or dolomite. Sorry I can't tell if it's that or sandstone without seeing it up close (like in my hand, don't worry about more pics). These rocks are made of calcium carbonate (limestone) or calcium magnesium carbonate (dolomite). Both of these minerals are slightly water-soluble and tend to increase pH through buffering (although it happens slllooowwwly). These rocks also commonly contain iron and may contain pyrite.

I'm not too too familiar with the geology of Kansas except that you aren't by mountains or deserts and you have a lot of prairie, which means...I can't use that to tell you the kind of rock.

One more question: take a piece of rock and try to scratch it with a) your fingernail, b) a penny, and c) a steel knife, and let me know if any of these scratch the rock. That will identify it for sure!

steve_58

I can't tell for sure without better picture but they sure look like sandstone to me. Here in Pennsylvania where i live we have more of it around then any other kind of rock i think .I used sandstone in my tank and some of it has that real slight glitter look and some has that reddish look some has an orangish look,some has a brownish look.Some of what you got also looks like a type of slate or shale.

CHoffman

I'm not worried about it raising the PH it's a Mbuna tank and they like high PH..These rocks are big to begin with and the workers building break it apart into pieces they need. What they can't use we get.. The rock on one side is very textured and brown, grey and orange like you see in the pics, with the glitter all over. The piece I'm holding now has very heavy "glitter", the other side where they have used a plane or something to break it about is smooth and grey like concrete.. You can see the difference in the rocks in the pic too. SOme spots are just grey and others have the brown and oranges. I did the scratch test on the part that is very textured and brown, grey, orange. My fingernail did nothing. the penny sort of made a faint white line but the knife made a more visiable line. ON the back where it's grey, fingernail did nothing, penny left a brownish, orange mark and knife didn't do anything....I really appreciate your help with this by the way. I'm completely uneducated on the different kind of rocks.

prairielilly

If it were limestone or dolomite, the fingernail or the penny would have left a mark because they are around the same hardness. A knife would have cut a slit.

Because none of them really made a mark, that means it's sandstone (the pieces aren't broken like shale or slate would be, which have a very distinctive character). A steel knife is slightly less hard than quartz. Sandstones are usually made primarily of quartz, so if it is sandstone none of those objects would scratch it.

I'm therefore pretty confident you have a sandstone, and the 'glitter' is due to quartz. There's a possibility of disseminated pyrite in sandstone, but there's no way to tell unless I could see the rock. It's relatively rare.

I think the only thing you may want to be concerned about/find out more about is whether or not it is bad for material with iron oxides to be in your tank. That colour is due to only that one thing, and it's a part of the rock so you can't do anything to it to remove it from the rock.

If it were me, I'd leave it in the tank and monitor my water like a hawk. Good luck

Edit: did a bit more digging (I've been out of school for a bit) - iron oxide is known in geology as hematite, which also gives terra cotta its colour. We put terra cotta pots in aquariums, so maybe all's ok (though it's part of fired ceramic in that case). Still trying to find anything about whether or not it's water soluble.

http://en.wikipedia.org/wiki/Sandstone

CHoffman

Thanks a bunch!!!. I really appreciate your help. The link that Mathas gave under "What about heavy metals" the 8th paragraph talks about iron oxides....It looks like I'm safe. Thanks again!!!...

prairielilly

Yay! I'm happy it's working out for you! (I should tell my mineralogy profs all that stuff was real-life useful too)

CHoffman

LOL...Yup, it's a great feeling when you can use information you learned in school in real life..There are so many things you never use so when you do use something it's awesome!!.

prairielilly

In my job I talk about rocks every day, but in terms of well logs and maps and computers and 'depositional environments' and theories, to try to figure out where the oil is...it's been a few years since I had to actually identify a rock. Thanks for the refresher!