Diatomaceous Earth

[Olympusman]

[WalterD]

Interesting set. Have you got a sample location for the earth or did you receive it sampled?

[Olympusman]

I am aware that there are various sample beds of diatomaceous earth, but the huge bag in my garage doesn't give me any source details.
I also found a non-chemical insecticide that is based on diatomaceous earth, and when I examined the sample, it was severly wanting in intact specimens.

Mike

[zzffnn]

I am aware that there are various sample beds of diatomaceous earth, but the huge bag in my garage doesn't give me any source details.
I also found a non-chemical insecticide that is based on diatomaceous earth, and when I examined the sample, it was severly wanting in intact specimens.

Mike

^ Very true.

I have this diatomaceous earth, bought from Home Depot as mechanical insecticide:https://www.google.com/shopping/product ... wAod_qME-Q

Diatom species there are very limited, small, plain and broken. But I did not spend a ton of time screening its wet mount either.

[Rudix]

I have been reading, with great interest, this and other 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!)
PS, if it turns out to be interesting I would be happy to share with others.

[Rudix]

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.









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



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

Thanks for looking!
Rudi

[Olympusman]

Lucky you.
From what I have found, commercial diatomaceous earth is milled to a sepcific size since it it used in water filtration systems. You have been fortunate enought to get access to unmilled samples. Go for it, man.
In addition, from what I have read, most deposits have unique species compared to other deposits. As I recently posted, my "swimming pool" earth had some (although) repetitive species and a search for two or three intact specimens might take one or two hours per session, whereas my "non-poisonous garden insecticide" yielded nothing, perhaps because it was milled too fine.

Mike

[Rudix]

Lucky you.
From what I have found, commercial diatomaceous earth is milled to a sepcific size since it it used in water filtration systems. You have been fortunate enought to get access to unmilled samples. Go for it, man.
In addition, from what I have read, most deposits have unique species compared to other deposits. As I recently posted, my "swimming pool" earth had some (although) repetitive species and a search for two or three intact specimens might take one or two hours per session, whereas my "non-poisonous garden insecticide" yielded nothing, perhaps because it was milled too fine.

Mike

Hi Mike.

Yes, it does look like a good find, I have already seen so many different ones it is impressive.

The sample I have was processed to some degree though. The good news is that the farmer said I could visit anytime and collect raw material, he seems quite interested in the whole idea!

So I will be planning a flight in that direction soon, since he has a runway on the farm (many farms have) it will be easy to visit.

For now I am experimenting with cleaning and separating the diatoms from the sand, my first quick attempt already yielded a far cleaner sample.

Thanks for your post that inspired me to go and look!
Rudi

[Cactusdave]

You are fortunate. That looks very good for a 'raw' sample. There are several contributors to the forum who have a lot of experience in cleaning up raw diatomaceous earth. I know Beatsy has done it for example, hopefully he and others will comment. You might get more and quicker useful feedback by posting this in a new thread.

[zzffnn]

Mike,

I admire your patience for scanning an hour for intact frustules. I gave up at 15 minutes on my pesticide earth.

Rudi,

Your sample looks interesting enough for a clean/mount, though it may not attract collectors who already have a reasonable collection.

I am sure you read about repeated freeze/thaw cycles and boiling in sulfuric acid and nitric acid. If you are not ready for boiling in acid, room temperature soak with concentrated (>30%) hydrochloric acid for 2-3 days will clean much better than no acid at all.

Repeated gravity separation and filtration with 30-500 micron filters will help too.

Hardcore diatomists would be able to tell you more, once you open a new thread, say in our techniques section.

[Rudix]

Mike,

I admire your patience for scanning an hour for intact frustules. I gave up at 15 minutes on my pesticide earth.

Rudi,

Your sample looks interesting enough for a clean/mount, though it may not attract collectors who already have a reasonable collection.

I am sure you read about repeated freeze/thaw cycles and boiling in sulfuric acid and nitric acid. If you are not ready for boiling in acid, room temperature soak with concentrated (>30%) hydrochloric acid for 2-3 days will clean much better than no acid at all.

Repeated gravity separation and filtration with 30-500 micron filters will help too.

Hardcore diatomists would be able to tell you more, once you open a new thread, say in our techniques section.

Thanks, yes, I have done a quick clean already just getting rid of some sand. I have no problem boiling it in acid so I will give that a try.

I have been looking carefully through a slide, made from water taken from close to the top after shaking a sample in water. I assume this will give me the smallest/lightest forms. A quick count ended when I got confused but I counted 53 shapes at that point. A lower down sample showed very different samples.

I now have a few containers of water taken from different levels of the original container, I am waiting for it to settle out before taking the next step. There are shapes I have not seen online on the web. Hope to document a few soon but I need to make better mounts than the wet ones I used today.

Fun, and a change from pollen!

Thanks for looking and the advice.
Rudi