Red Rocks Are They Aquarium Friendly?

[Masami]

I would like to aquascape my fluval chi with some plants and rocks to make a more life like environment, the rocks in the picture below I received with a second hand tank I purchased so I would like to gauge opinions on whether they are safe to use in such a small tank environment (with a dwarf puffer) as they appear to be mineral rock at a first glance (shiny crystal like bits in them).

Just peoples general thoughts would be good.

 

[garyspence84]

Rocks that have mixed colours, usually mean they've got metals in them, but I'm no expert. I would personally avoid them if at all unsure.
You could always do the vinegar test. Pour some on the rock, if it starts to fizz, don't put it in. But of nothing happens, its safe.
But I would try googling the rock to try find out it that IS some kind of metal that's through it.

Hope this helps, good luck

G

 

[Benj]

Hard to say from the picture, are the darker areas of the rock crystalline (ie interlocking crystals without gaps in between? If they are-

A good way of identifying a carbonate is to see how hard it is- in general carbonates scratch with a nail or a knife tip, silicates do not.

Colour does vary hugely in rocks due to their chemical makeup and wether they contain metals but isn't really any use in determining whether it is safe in an aquarium, the main thing is avoiding water soluble rocks which will change the pH of the water.

 

[DrRob]

Vinegar isn't really strong enough to be reliable, it's a weak acid and is often fairly dilute when you get it for food use. Try a stronger acid such as limescale remover.

You could also lick it, if bits come off it's going to fall apart, and if it's salty it's a bad move.

You've got something there that looks like quartz inclusions. A close up would help, but knowing where the rocks came from would help even more. Overall, if in doubt, don't put it in with anything you care a lot about.

 

[Benj]

Having had a closer look at that picture I've no doubt that those will be absolutely fine in an aquarium. Seeing the picture full size I could pretty much tell it's a silicate composition rock, which will not dissolve on you any time soon can't tell you 100% if its sedimentary or igneous but due to the much larger quartz crystals among a finer matrix, and lack of any structures or lineation I'd bet my left nut that it's a granite of some kind. The red/pink crystals are likely to be a feldspar mineral, again, a silicate so no worries

Unless the rock literally crumbles like mud/a brick/or you do test it and find CaCO3,.... I say rock on

Just a note on colour- true, it is metals which tend to give minerals their colour, but the way a crystal lattice is formed means that those metals are trapped within the silicate 'cages' of the molecules, where they are held by strong ionic bonds that only high temperatures or pressures etc can break. Issues with leaching heavy metals are generally non existent unless you were to introduce a pure form of such a metal- lead plant weights for example!

The FAQ/guide on aquarium rocks on here is a fantastic effort and does get the basics correct in general, although it really could do with a fair bit of editing and revision as there quite a lot of misinformation there, it could be much more concise- almost flow chart like,,, I'd offer to help out myself but I've only been here a couple times and I've no idea of how to go about it!

Peacee