# Safe rocks for the freshwater tank?



## solarz (Aug 31, 2010)

Does anyone pick up rocks from unconventional sources such as garden centers or in lakes and streams? If you do, how do you tell if a rock is aquarium safe? (Assuming you don't have a bottle of vinegar handy when you visit a garden center or take a walk along the lake.)


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## igor.kanshyn (Jan 14, 2010)

I have done this. Look for granite rocks, they are safe for sure.
Some rocks like limestone will raise your hardness and pH. Check the rock's look.

It's also a good idea to wash and boil the rock before using.


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## Jamblor (Dec 21, 2010)

Like Igor said, stay away from rocks that contain calcite (limestone, marble) and stick with rocks that are silica based (granites are the easiest to find) Also metamorphic types such as gneiss, schist, slate are good choices. 

Basically if you tend to stick to darker rocks you should be safe. 

If you want to look for rocks in the GTA, the natural rock and most common you will find will be various sedimentary rocks. Mostly you will find shales or mudstone/siltsone and sandstones. They are brown to dark grey and have a fine sandy texture. You may occasionally find granite that is mostly pink in colour with individual grains that are large enough to see with the unaided eye. 

Don't use any that are light colour or white and that have individual grains that are indistinguishable and or fossils. They will most likely be limestone or dolomitic limestone. They are native to the Niagara Escarpment. 

And as already mentioned boil and make sure they are clean.

Source: I'm studying geology at university


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## solarz (Aug 31, 2010)

Thanks, Jamblor, that's very helpful. I'll have to keep those tips in mind next time I look for rocks.


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## theeyrietrainer (Dec 9, 2010)

Jamblor said:


> Source: I'm studying geology at university


Sorry to hijack your thread, but do you think rocks collected from a river or a lake would be tank safe as well? I have an assortment of rocks I picked up from the Fraser River that I want to add to my tank..


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## Jamblor (Dec 21, 2010)

I'm not too familiar with Western Canadian Geology but from what I recall the Fraser Valley is mostly sedimentary rocks with a lot of shale. When I was in the rockies north west of Banff I noticed a lot of shale, Burgess type. 
In any case, if it is shale it will be safe. (It's basically the softer un-metamorphosed version of slate) However, watch out for any fossil shells as their calcium content may affect water parameters. 

If you have pics I might be able to tell you better.


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## JAM (Dec 14, 2010)

Jamblor said:


> I'm not too familiar with Western Canadian Geology but from what I recall the Fraser Valley is mostly sedimentary rocks with a lot of shale. When I was in the rockies north west of Banff I noticed a lot of shale, Burgess type.
> In any case, if it is shale it will be safe. (It's basically the softer un-metamorphosed version of slate) However, watch out for any fossil shells as their calcium content may affect water parameters.
> 
> If you have pics I might be able to tell you better.


How about these rocks Jamblor?
http://gtaaquaria.com/forum/album.php?albumid=53&pictureid=375
I got them from a friend's farm (Right) and the black stone and the rest of the Rocks are from Van Beeks garden store....Thanks.

JaM


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## Jamblor (Dec 21, 2010)

JAM said:


> How about these rocks Jamblor?
> http://gtaaquaria.com/forum/album.php?albumid=53&pictureid=375
> I got them from a friend's farm (Right) and the black stone and the rest of the Rocks are from Van Beeks garden store....Thanks.
> 
> JaM


Hey JaM,

They are a little bit hard to tell from the pictures but I do believe they are of granitic origin. The lighter one on the right looks like a gneiss. Is your friends farm in Ontario? 
In any case they look like they are fine.

I'll try and make a complete writeup to aquarium safe rocks with pictures this weekend or tomorrow if the school is closed. Perhaps it could be stickied?


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## JAM (Dec 14, 2010)

Jamblor said:


> Hey JaM,
> 
> They are a little bit hard to tell from the pictures but I do believe they are of granitic origin. The lighter one on the right looks like a gneiss. Is your friends farm in Ontario?
> In any case they look like they are fine.
> ...


Thanks Victor. yeah, his farm is in Milton too, Escarpment area near Rockwood. You can see the other rocks in the album...your knowledge is an asset for this forum.


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## Jamblor (Dec 21, 2010)

JAM said:


> Thanks Victor. yeah, his farm is in Milton too, Escarpment area near Rockwood. You can see the other rocks in the album...your knowledge is an asset for this forum.


Ah ok. It can one be one of two things then. Either a gneiss which is still my guess, or a limestone/dolostone, but I don't think so since it has the wrong texture. It's kind of interesting how such a rock got to southern Ontario since gneisses are found in cottage country, north of Barrie. They hitched a ride during the last ice age from glaciers.

But a note about rocks found near the escarpment. They are limestones and dolostones. Both types contain calcium carbonate. And in dolostones case, magnesium-calcium carbonate. Both would likely affect water quality.

And no problem, I'm glad I can use my knowledge to aid this great community


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## AquaNeko (Jul 26, 2009)

Anyone know what type of rocks are up by the bluffs?


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## Jamblor (Dec 21, 2010)

AquaNeko said:


> Anyone know what type of rocks are up by the bluffs?


The Scarborough Bluffs are the leftover glacial till(sediment) from the last ice age. The actual bluffs aren't cemented too well hence why it's eroding so fast.
If they did cement themselves they would be a sandstone, or siltstone.

You can also find glacial drop stones within the sediment as well. These will likely be larger clasts if shales, sandstones, or siltstones, and even granites.

PS. the university is closed today So I'll try and work on the start of a guide today that will include the various different rocks and where you can find certain rocks around the GTA.


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