Are these rocks ok for aquarium use?

[KLee79]

First off, I live in columbus, OH. Where I live there is a small rock quarry in our housing developement. Its filled w/ all kinds rocks but mostly what looks like sand stone or some sort of slate/shale?? Heres a couple rocks I picked up and I'm curious if I could use these in the aquarium? Oh and thats my lil tag-along rock hunter. Anybody know their rocks?? lol and I'm not talking about the little white ones haha

 

[Ancient_Fish_Master]

try soaking it in some water, if the rocks break down then dont use them other than that, a good scrubbing and put it in the tank

 

[KLee79]

yea I thought they would be ok. I've heard of people pouring vinegar on it to see if there was any reaction to it.

 

[ravensfan73]

Vinegar is a good judge. Before you wash them, pour a few drops of vinegar on each rock, if they start bubbling, then they are not safe, but 90% of rocks are usually ok. I get all my rocks from the creek by my house and have had no problems thus far.