Aquarium Rock

Question
Greetings,
How can I tell if a decorative  rock is safe to place in my new 29g tank? I know different materials will affect the chemistry, is there a general rule-of-thumb? Or should I just take it to the Fish Store and let them look at it? By the way it's a chunk that almost looks like dark red glass but part of it is clear. I'm sure that doesn't help, but I bet tour answer will! Thanks!
Paul

Answer
Hello,

I would not add any foreign rocks to your aquarium unless you can identify exactly what it is, and if you can boil it first AND if you can monitor it during this boiling time to make sure it does not show any evidence of erosion.

In general, I usually recommend to keep foreign rocks out of your aquarium. Not only can they change water chemistry, but they can leach poisonous substances into the water.

I hope this helps.

Regards,
Stephanie