Rock Identification & Suitability

[Burtie]

Hi,

I've a few unidentified rocks that I have from when I was a kid. If anyone can help identify them it would be very appreciated.

Is there a general rule for what rocks can be used in a tropical aquarium? How can they be assessed for suitability?

Thanks.

My thoughts:
1 - Some sort of calcium based rock 2 - Granite 3 - Pumice (it's really light) 4 - Granite 5 - Quartz 6 - Sandstone with quartz
7 - Red limestone (think it came from Grand Canyon) 8 - ??? quite light; looks volcanic 9 - Limestone 10 - Hemitite
11 - Amethyst or Rose quartz

 

[NinjaSmurf]

Clean them up and pour some vinegar on them, if it fizzes they shouldn't go in the tank, if it doesn't fizz then they're ok. Just scrub them really good with hot water and a toothbrush.

 

[Burtie]

Clean them up and pour some vinegar on them, if it fizzes they shouldn't go in the tank, if it doesn't fizz then they're ok. Just scrub them really good with hot water and a toothbrush.

Simplicity in the extreme. Thanks for that! Will do.

Also just found FF.net rock info