# Has anyone used Geodes in a planted tank?



## theshadybird (Sep 25, 2012)

The most basic way to test how rocks will affect your water is to put them in water (a bucket works) and test the PH and hardness over a period of a few weeks. It's time consuming, but at least then you'd know how it'd affect your water. Can't wait to see pics of the setup!


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## HighDesert (May 8, 2012)

You can get botryoidal geodes, which will have smooth formations inside, instead of sharp quartz crystals. Several types of rock form these types of geodes, such as agates and some rare quartz. You could also go with drusy (lots and lots of little tiny crystals amassed inside the geode), which tend to be MUCH less sharp. As theshadybird was saying, test anything you might put into your tank for a few weeks prior to actually using it. I would also recommend giving any cut rock you're going to put into your tank a REALLY good scrubbing with white vinegar and hot water and rinsing thoroughly, as some of the polishing compounds contain high levels of iron, aluminum or other things that could contaminate your tank.


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## lochaber (Jan 23, 2012)

I may be wrong on this, but I'm pretty sure most geodes are quartz or some color variant (amethyst, rose, agate, etc.), which are all perfectly inert and safe for aquarium use.

There may be some concern over what the geode formed in, if there are any carbonates on the outer shell, etc. 

If you can post a pic of the non-crystal part of the geode, that might help. 

If it does have some stuff on the outer part, you may be able to give it a soak in some acid for a while, and then several freshwater rinsings to get rid of it.

tl,dr: A geode will probably be fine.


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## GMYukonon24s (May 3, 2009)

That's interesting


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## JerSaint (Oct 22, 2012)

Here are photo's of the outside and inside of one of the geodes. 
Thanks!


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## Action53 (Jul 28, 2012)

That's gonna look so sweet


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## arsNatura (Sep 13, 2012)

I have used clear quartz and amethyst before. They are safe in tanks, but can be worn down/dissolve by water over time. Not sure how long that would take, but keep that in mind. I am not sure how long I had my crystals in the tank but probably not longer than a year so I can't tell you what the long term effects would be


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## lochaber (Jan 23, 2012)

thanks for the pic.


I can't say for certain, but the inside xls look pretty quartz-like.

If you have some sort of acid, I'd try dripping a bit of it on the outside, especially the lighter colored patches.

If I remember correctly, I think most geodes form out of igneous rocks (which are generally ok), but there are always exceptions, and there are a lot of cases where carbonates (or other somewhate soluble minerals) can get deposited amongst otherwise inert rocks. 

I'd like to say it's excessive worry, but I'd still want to acid-test the outside of that geode. I'm pretty sure the inside is fine.

If you can't be bothered to test (or if it seems bad and/or ambiguous...) you could always coat the outside with resin (and, considering what HighDesert said, the cut/polished face as well), which should render it aquarium safe after it's cured...


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## Christee (Feb 1, 2020)

*Using resin to coat geodes*

I would like to know what brand or kind of resin to use to coat the geodes that makes it safe for my aquariums? Thanks very much for any advice!


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