Coral Stone/rock

[IAmATeaf]

During our holiday to Thailand my kids picked up some coral stones which were washed up on the beach which they've bought back. Ignoring if bringing back dead coral stones is legal or not as the thought never occurred to me can I put the stones in my freshwater tank?
 
I've done a quick google and have found post that say strictly no but others saying they've got them in their tank without problems.
 
I can post pics of the stones if that makes a difference.

 

[sputnick]

I would imagine as long as they are long dead and you rinse them of any salt yes. But keep in mind it may mess with the Ph level of your water. To safely test you can leave the rocks in a bucket of water for a week or so and measure the Ph of the water before and after.

 

[phishyphil]

Coral, or anything from the sea in freshwater tanks is usually a bad idea, almost certain to leech "SOMETHING" into the tanks whether its a bacteria, calcium, chemical properties that will affect pH

 

[IAmATeaf]

Sorry for the late reply and thanks for the replies so far. I had a sneaking suspicion that it would be a bad idea. I've taken some pics of the rock and have done the vinegar test and none of them fizz. I've also soaked them in boiling water and the 2 beige/sand coloured rocks actually float, thought they'd sink after a while but a good half an hour later and they are still floating.
 
The white one on the left looks like a chunk of quartz, no fizz so should be safe? The white oval one at the bottom of the first pic sinks and as I said above the 2 others float. If anybody has any comments after looking at the pics I'd appreciate it, currently I'm only going to put the quartz rock in the tank tomorrow after a water change and clean.
 

 

 

 

 

[IAmATeaf]

After an hour or so the the 2 beige rocks that floated actually sank and i've been told on another forum that they may be pumice stones.