Question About These (Found) Rocks?

[KevJ87]

Hey guys, 
 
I have never been one to go out and find objects for my aquarium but this 29 gallon tank setup is going all natural baby 

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So I went out and found some rocks ( tons here where I live ) the problem is I did the fizz test like you guys suggested, I used white wine vinegar and I scrapped the rocks to make sure it was only the rock it was reacting with, NONE of the rocks fizzed out of about 3 or 4 different types which kind of freaked me out. I am thinking the test didn't work since I didn't receive 1 bad fizz.
 
Here is a picture of the rocks was hoping you guys could provide some insight into whether or not they are safe or what types they are since I am a terrible geologist 

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***** For some reason i won't allow me to use images.... from either tiny pic or image shack.. although it let me before ******
 
Here is the link to the rocks
 
https/imageshack.com/i/km4OfVBVj
 
 
And here is one of the tank so far !
Black tahitian moon sand /// 4 plants so far  /// plan to build a center rock structure  Slate and Supporting rocks
 
https/imageshack.com/i/iqzIZ7vij
 
 
 
 

 

[EllieJellyEllie]

They should be fine. The only tocks Ive seen fizz are limrstone because they raise pH. And those are safe. Youre good

 

[tunagirll]

Looks like two granites and two mudstones - think you're good to go!

 

[KevJ87]

I read that mudstone is not safe though due to breakdown is that not true ?