What types of rocks to use

I recently atarted up my 130 gal freshwater tank and it looks pretty cool. (hope to post pic's soon).
Then while in the yard I remembered I had a bunch of flagstone left over froom another project.
Here's my question. Is normal garden variety flagstone safe to place in a stock fish tank? I was hoping to use some of it to make some natural looking formations for my fishy freinds to play and hide in.

Hi Dragon...
A lot of times you can test a rock by placing it in vinegar.
Wait awhile...
If it fizzes a bit..don't use it. Limestone is a no-no..as it is one that will leak toxins into your water.
Also sandstone is going to leak calcium into your tank..so that would not be good.
Far as I know...flagstone should be fine.
You may want to boil it first too.
If it does not flake off after it has cooled...should work alright for you.
If this is for an african tank..
it will be great..as it will elevate the PH a bit..which africans will love.
I had a list awhile back I found & posted on our old forum...but i can't find it. It had all the aquarium safe natural stones listed.
I will try and see if I can locate it again.

I hope you find the list. Decorations sold specifically for aquarium use no doubt cost more than similar items purchased on the open market, but when you consider the impact of putting the wrong thing in your aquarium, maybe it's better to spend the extra money.

Sorry JohnA...
I looked thru all my files..and sadly..
I think it is lost along with some other good information from our old forum.
Bummer!!
* I would still use the vingegar & boiling test on rocks purchased at the LFS. Even those may or may not raise PH levels. A lot depends on what type of fish..and their PH requirements.*

Thanx for the quick replies.
My brother keeps Pink Parrot fish and 1 day he looked into his tank and found 30 plus babies of which he gave me 12. I have 6 that survived. Boy were they tiny when I got them about 16th of an inch or so. The survivors are pushing 3/4 of an inch.
Any way, I take all the precautions I possbly can before I place something in my tank(s). Just was'nt sure on the garden variety flag stone. Hope it checks out fine because it would look really cool in my tank. I'll post pictures as soon as I figure out how to resize them.

That sounds exciting!!
Yeah..can't wait to see some pictures!!
Parrotfish have such cute personalties... love how they come to the front of the tank with those big eyes.
If you want a "free" and easy way to re-size your pic.s...this is what I do.
Go to www.photobucket.com
Doesn't cost a thing to join.
Upload your pic.'s from your files..
and then copy & paste the IMG code here into your post on the forum. Simple..