# Hematite for planted tanks



## Jeff Kropp (Apr 25, 2004)

Just back from my vacation to Minnesota. Returned with hematite noduals weighing down my suitcase. Has anyone here tried hematite rocks in a planted tank?
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Jeff


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## mr greenjeans (May 24, 2004)

Hey, Minnesota, that's where I live! You must have been up north on Lake Superior? Sure that hematite isn't gold (or maybe I've got my minerals mixed up)?

Sorry, no advice on the hematite, but one thing we do around here is search for Superior agates. A nice collection of agates can make a nice accent to a tank.

Hope you enjoyed your vacation up here. Did you get caught by some cool temps? Catch any fish?

My furnace actually kicked on a few weeks ago. It's been a beautiful. cool summer here this year.

Duh, I just realized this under the fertilizing forum...you must be after the iron.


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## Jeff Kropp (Apr 25, 2004)

mr greenjeans said:


> one thing we do around here is search for Superior agates.


Well I was out with rockhounds but we were collecting fossils, hematite and goethite on the waste piles around Hibbing. Our tour guide was both a rockhound and former Hull-Rust miner. We visited the Hull-Rust mine and the Hill-Annex mine. Our guide told us of the time he dodged a 26 pound rock flying into his Calumet school yard as a result of blasting in the Hill-Annex mine.

Did only 1 day of swiming but caught some northerns and walleyes on Bottle Lake. The cool temps have retarded aquatic plant growth in the lake this year. Many typically good fishing spots were bare of their normal vegitation and provided poor fishing. Minnows seemed suspended mid-lake and that made locating game fish even more difficult. Spent part of my swimming day examining plant species and think there is good potential for great minnesota biotope tanks. Almost brought home a sack of plants but decided against a new biotope tank at the last minute.
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Jeff


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## McFinn K. (Aug 11, 2004)

Hi, 
I read up on this stuff awhile back when I was trying to develop the "ideal" substrate. I don't know about the hematite, but the goethite maybe good. It depends on whether the goethite is still FeOOH. The OH groups are what you need for PO4 binding/adsorption, if I remember correctly. Neither will give you significant iron (I don't think this stuff is that soluble) if that is what you are looking for. Hematite has already been oxidixed too much for significant PO4 adsorption. Cheers,


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## pineapple (May 4, 2004)

In what form is the hematite (Fe2O3)? Granular? Colouration?

It is likely hematite granules contain impurities such as titanium.... and there may be other iron minerals present including limonite and magnetite.

If you are hoping that hematite granules would contribute to make an Fe rich substrate, that would depend on a number of factors. Hematite in general is fairly stable.

Andrew Cribb


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## Jeff Kropp (Apr 25, 2004)

pineapple said:


> In what form is the hematite (Fe2O3)? Granular? Colouration?


The rocks I chose are rounded noduals of shiny black rock that rusts very fast and gets a red iron oxide coating. I think this is the same stuff they make jewlery outa but I wonder why it doesn't rust in the trinket stores. Speculation amoung the rock club was that these samples were from the Cambrian layer and were rounded by wave action. They claimed this ore was more than pure enough for smelting. Mixed in with the same till pile was plenty of goethite but it was mostly found in thin layers on sharper shards of rock. The goethite didn't show the same propensity for rusting that the hematite does. I really liked the look of these rocks when black and shiny but the rusting kinda dimmed my enthusiasm for aquascaping with them. I have them in a bucket now to see how they behave submersed.
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Jeff


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## pineapple (May 4, 2004)

Interesting. I know that a vast amount of iron is mined in the mid-North in the form of Hematite rich sedimentary strata. Nodules, as you say, can come from shallow littoral or not so shallow sea floor deposits. Manganese nodules are found in deeper sea floor areas.

It's possible that groundwaters being slightly acidic or chemically active in some way have accelerated the hydration into rust or Limonite (FeO OH nH2O). As you say, the best way is to keep it in a tub at warm temperature and see how it behaves over a period of a month.

Andrew Cribb


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