Can anyone ID these rocks?

[DonnieP]

Can anyone help me on these two rocks? I would like to know what kind they are and if those black veins in them are ok for a tank.. HELP!!!

http://www.catfishheaven.net/background/30.jpg

http://www.catfishheaven.net/background/31.jpg

[Pink Pat]

DonnieP,

I'm certainly no geologist, but those appear to be granite.

I'd say, black veins or not, that those would be OK for aquarium use. You can hold out for more opinions for more/better confirmation of their suitability.

HTH

PP

[Dapple2]

It's really tough to id rocks from pics. Perhaps you could take it down to your local community college or university. There might even be a gem and mineral society nearby that could help ya out. Most of the rock hounds I've met have been more than willing to look stuff over ;) Otherwise we'd need to know it's hardness and other fun and interesting parameters....

[Dahlia]

If you want to find out if a rock is aquarium safe, fill a bucket with water and use a water hardness test before you add the rock. Record that number and then add the rock to the bucket. Wait a week and then do another water hardness test. If the hardness has gone up, then it isn't safe for your aquarium.

As far as I know the only other worry than pH for adding rocks is if it carries parasites or other harmful organisms. You can get rid of these by boiling them.

I've only done this once so someone with more background in chemistry may know more about this than I.

[a_free_bird73]

It very rare to find a rock that is not suitable for an aquarium, because if it was chemically unstable, it would have gotten broken down a long time ago.

The only thing you have to watch for is the pH of the water. some rocks will buffer water pH closer to 8 and that makes them ideal for fish that require high pH. Other than that, you just need to either boil or better chlorinate/dechlorinate the rock before use.

[Frameshift]

Pour some vinegar on it. If it bubbles and fizzes than the rock will buffer the PH. If nothing happens, the rock is stable.

(Think vinegar and baking soda, acids and alkalines react, so if the rock is alkaline (buffers PH) it will react with the vinegar.)

[Nippy]

It looks like it is igneous in origin (volcanic/plutonic) and may possibly be basalt. Without being able to examine it in my hands, I can't be 100% sure.
I have plenty of basalt among other rock types in my tanks and have never had a problem. Do the vinegar test if you are still unsure.

[Matak]

I thought it might be basalt myself, maybe with some quartz veining.

[clayt101]

I agree...Basalt.

[DonnieP]

Thanks folks, I kinda thought it was Basalt to, thanks for your help!