Diatomaceous Earth - Hidden treasures

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RudiV
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Diatomaceous Earth - Hidden treasures

#1 Post by RudiV » Wed Mar 29, 2017 11:39 am

I have been reading, with great interest, posts about Diatomaceous Earth and all the possibly hidden diatom treasures to be found. All this got me doing some research on local (South African) sources of Diatomaceous Earth. I was happy to discover that there are large deposits in South Africa with some mining started.

A few calls and email put me in contact with a person who had deposits on his farm and soon a "sample" was organized so the wait started, would there be any usable specimens left in the raw product?

Anyway, the sample arrived today, all 5kg's of it! I could not wait to get it under the scope. Well, the good news is that there are plenty intact diatoms visible the moment you look at the uncleaned sample. Sure, there is quite a bit of fine sand and broken diatoms but within a few seconds I could see lots of different intact shapes.

Now I need to learn a new skill quickly, how to separate/clean the good stuff from the junk!

As soon as I have some reasonable clean samples I will post a few photos.

Rudi (Frantically reading up on diatom cleaning techniques!)

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Johann
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Re: Diatomaceous Earth - Hidden treasures

#2 Post by Johann » Wed Mar 29, 2017 11:52 am

Nice project - can't wait to see the results. Just the one thread on this forum is going to keep you reading for a while ;)
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RudiV
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Re: Diatomaceous Earth - Hidden treasures

#3 Post by RudiV » Wed Mar 29, 2017 1:26 pm

Johann wrote:Nice project - can't wait to see the results. Just the one thread on this forum is going to keep you reading for a while ;)
Hi Johann.

Yes, the one thread alone makes for some interesting reading!

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Re: Diatomaceous Earth - Hidden treasures

#4 Post by billbillt » Wed Mar 29, 2017 1:56 pm

Looking forward to your photos..

BillT

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Re: Diatomaceous Earth - Hidden treasures

#5 Post by RudiV » Wed Mar 29, 2017 2:23 pm

A few quick random images. I simply put a tiny speck of the powder into a drop of water on a slide and slapped a cover slip on. No attempt was made at cleaning or selecting yet.

Images taken with a 10x objective, not stacked.

Image

Image

Image

Image

The one below was with a 5x objective trying to get a general impression of the sample.

Image

I think this could keep me busy for a while....

Thanks for looking!
Rudi

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Re: Diatomaceous Earth - Hidden treasures

#6 Post by billbillt » Wed Mar 29, 2017 4:36 pm

Oh yes!!.. You are going to have lots of fun!!...

BillT

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Re: Diatomaceous Earth - Hidden treasures

#7 Post by KurtM » Thu Mar 30, 2017 12:36 am

I don't see where you have a lot of cleaning to do, more like separating frustules from sediment. But this is a vexing problem that diatomists have been struggling with for a long time, and I am sorry to say I cannot point you in any particular direction on it. If you discover an effective method, please by all means do share - we're desperate!

I imagine veteran diatomists like Kemp, et al, have devised methods, but if so, I am unaware of what they are. Some methods I've heard of that seem to have promise are swirling in Petri dishes or watchglasses and pipetting off, and the newest, "audio sorting", where the vessel is placed upon a small speaker, which is then connected to a frequency generator, and the frequency adjusted for best effect; then pipetting off. If you don't have a frequency generator, perhaps an amp delivering some nice Jimi Hendrix ballads might serve?

That's some mighty nice DE you got there. From the buzz on another forum, I understand most DE obtained today actually contains little in the way of frustules, suggesting that the deposit sources are playing out. What I picked up at my local hardware store was definitely entertaining, but still not as good as yours appears to be.
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Re: Diatomaceous Earth - Hidden treasures

#8 Post by RudiV » Thu Mar 30, 2017 3:40 am

KurtM wrote:I don't see where you have a lot of cleaning to do, more like separating frustules from sediment. But this is a vexing problem that diatomists have been struggling with for a long time, and I am sorry to say I cannot point you in any particular direction on it. If you discover an effective method, please by all means do share - we're desperate!

I imagine veteran diatomists like Kemp, et al, have devised methods, but if so, I am unaware of what they are. Some methods I've heard of that seem to have promise are swirling in Petri dishes or watchglasses and pipetting off, and the newest, "audio sorting", where the vessel is placed upon a small speaker, which is then connected to a frequency generator, and the frequency adjusted for best effect; then pipetting off. If you don't have a frequency generator, perhaps an amp delivering some nice Jimi Hendrix ballads might serve?

That's some mighty nice DE you got there. From the buzz on another forum, I understand most DE obtained today actually contains little in the way of frustules, suggesting that the deposit sources are playing out. What I picked up at my local hardware store was definitely entertaining, but still not as good as yours appears to be.
Hi KurtM.

It does appear cleaner than I hoped for, a quick wash and pipetting session produced samples with just about no sediment. But I had a quick look at the sediment at the bottom and it does contain some interesting forms not found higher up. I suppose it is all part of the fun, trying new methods. I actually do have a frequency generator (HP) that was acquired for another hobby (Amateur radio) so as a fun experiment I will give the sound-separation method a go. But I suppose some Jimi Hendrix could be more fun!

I am looking forward to also collecting a raw sample, should have even more complete forms, they are only starting to exploit this deposit and apparently it is quite large. Interesting point is that these are fresh water forms as they are the result of a huge, shallow inland fresh water lake that dried out and now the area is semi desert.

Thanks for the advice!
Regards, Rudi

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Re: Diatomaceous Earth - Hidden treasures

#9 Post by Charles » Thu Mar 30, 2017 12:47 pm

Looks like some interesting stuff Rudi!

No matter how hard I try, the larger and heavier forms still get mixed in with the heavy non-diatom material which would normally be thrown out. I never throw out the heavy sediment now since I can pick out the diatoms from them.

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Re: Diatomaceous Earth - Hidden treasures

#10 Post by RudiV » Thu Mar 30, 2017 5:18 pm

Charles wrote:Looks like some interesting stuff Rudi!

No matter how hard I try, the larger and heavier forms still get mixed in with the heavy non-diatom material which would normally be thrown out. I never throw out the heavy sediment now since I can pick out the diatoms from them.
Yes Charles, every time I look is see new shapes, maybe noting special but all new to me!

I suppose picking them from the sediment is the best way, now I just need to practice the picking bit! I also need to look at mountants, at the moment the contrast I am getting is not great.

On that note I played around a bit today, still random images from the raw sample but experimenting to get more contrast.

40x objective, wet mount.

Image

Image

I will have the first semi cleaned samples under the scope by the weekend, looking forward to documenting what I find in the sample.

Thanks for all the comments!
Rudi

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Re: Diatomaceous Earth - Hidden treasures

#11 Post by MicroBob » Mon Jun 19, 2017 8:26 pm

Hi Rudi,

from what I know it is useful to put the material through different sieves before sedimentation. Big diatoms and small sand particles sink down at the same speed, so sedimentation of the whole sample doesn't really work.
Here in Germany you can buy stainless steel sieve material with mesh openings from 20µm to 500µm on ebay.
It can easily be fixed at the bottom of a plastic tube by welding with a soldering iron or hot nail.

Bob

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Re: Diatomaceous Earth - Hidden treasures

#12 Post by Hobbyst46 » Mon Oct 09, 2017 4:19 pm

Hi Rudi
Diatom separation is apoarently a tough mission that challenges geologists, paleontologists and other researchers.
There us a sophisticated method acronymed SPLITT. It is a separation of diatoms from other stuff by means of selective sedimentation or flotation in a laminar water flow. The challenge is to build or acquire a shallow water tunnel where you control the flow rate. Google can show you that it was recently applied for diatoms. Appears to be more interesting than brute-force sieving...
Hobbyst

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