Rock Hounds??? would this be a bad rock, to add to a tank...

[Magnum Man]

I'm in southern Minnesota USA, so there is no guarantee, but unless someone transplanted it, it's likely native to my area... it's grey green in color ( so copper is a worry ), but seems to have "fool's gold" crystals visible on one side... any guesses to what it is, & if it would be a problem to add to an aquarium, that may now, or someday contain shrimp???

 

[GaryE]

I'm no rockhound, but I would test that rock. Put it in a container of RO water, which you have measured for hardness. Leave it for a couple of months, and then remeasure. Lots of things can make a rock greenish - copper, other minerals, and I'm told even asbestos. It all depends on where you are.
I constantly find distinctive rocks on the beach across the road, but generally, after a short time in an aquarium, they look alike with a little algae.

 

[Magnum Man]

usually Iron Pyrite, normally stays more gold color, and less brown, we we have a lot of it in our area, so it's not unusual around here, but the rock's color is unusual for this area... I have a TDS meter, so I could give it a soak... it seems pretty hard...

 

[WhistlingBadger]

I'm guessing those crystals are micah, but hard to tell. I recommend getting a hold of a university geology department and asking them. Those people love to talk about rocks. But in the mean time, I wouldn't use it unless I knew for sure what it was.

 

[connorlindeman]

Pour a little strong white vinegar on it. See if it bubbles.

 

[Magnum Man]

I don't think it's in the lime stone family...

 

[WhistlingBadger]

Vinegar will tell you if it will mess up your hardness, but it won't tell you about any other toxins or minerals that might be present. I would especially be worried about copper and iron. Copper will nuke your shrimp, of course, and iron can cause algae blooms. And who knows what else is in there.

 

[Colin_T]

If it's from a clean area and hasn't been sprayed with anything it should be fine.

If you're worried about copper, do what Gary suggested and put it in a container of distilled water and test the water for copper a couple of weeks later. I doubt there would be enough leaching off the rock to cause problems to inverts in a big tank like yours.