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Oamaru diatomite
Posted: Tue May 19, 2020 9:16 pm
by Wes
Does anyone know a source of Oamaru diatomite? Scoured the web but couldn't find any, maybe you guys know where one could get a hold of this.
Re: Oamaru diatomite
Posted: Wed May 20, 2020 1:11 pm
by 75RR
All I can suggest is that you contact rnabholz, he may have a secret source.
Oamaru I:
viewtopic.php?f=6&t=6579
Oamaru II:
viewtopic.php?f=6&t=6584
Oamaru III:
viewtopic.php?f=6&t=6708
Oamaru IV:
viewtopic.php?f=6&t=6718
Re: Oamaru diatomite
Posted: Thu May 21, 2020 6:22 am
by Wes
Thanks 75'
From what I gathered this particular diatomite is no longer exported for reasons that were not entirely clear to me.
Re: Oamaru diatomite
Posted: Thu May 21, 2020 8:22 am
by MicroBob
There were several places to collect diatomite in Oamaru area. As far as I know these usually were on private land and unimpressive in size, e.g. a bit of diatomite looking from under the grass on a cow pasture. Some of these sources will have been used up or simply bulldozered since.
I once borrowed a bottle of Oamaru diatomite and was astonished to find lots of broken shells (sometimes of very big diatoms) and very few intact frustules. So the slides one knows from Oamaru diatoms are the result of some hard work. The reputation of Oamaru diatoms probably comes from the fact that it is faily nice and diverse for a diatomite and one doesn't have to leave the house to work with it. In my view it is more worthwhile to spend the time on freshly collected diatoms.
Bob
Re: Oamaru diatomite
Posted: Thu May 21, 2020 8:39 am
by Hobbyst46
MicroBob wrote: ↑Thu May 21, 2020 8:22 am
...In my view it is more worthwhile to spend the time on freshly collected diatoms.
The collection itself is an enjoyable adventure!
Re: Oamaru diatomite
Posted: Thu May 21, 2020 5:46 pm
by Wes
MicroBob wrote: ↑Thu May 21, 2020 8:22 am
There were several places to collect diatomite in Oamaru area. As far as I know these usually were on private land and unimpressive in size, e.g. a bit of diatomite looking from under the grass on a cow pasture. Some of these sources will have been used up or simply bulldozered since.
I once borrowed a bottle of Oamaru diatomite and was astonished to find lots of broken shells (sometimes of very big diatoms) and very few intact frustules. So the slides one knows from Oamaru diatoms are the result of some hard work. The reputation of Oamaru diatoms probably comes from the fact that it is faily nice and diverse for a diatomite and one doesn't have to leave the house to work with it. In my view it is more worthwhile to spend the time on freshly collected diatoms.
Bob
Thanks for the insight Bob! Would you know of another particular location that provides good diversity of diatoms (fossil species for example). I've just tried my first diatom cleanup but I find at most 3-4 dominant species and occasionally the odd one out.
Re: Oamaru diatomite
Posted: Thu May 21, 2020 6:39 pm
by Hobbyst46
Wes wrote: ↑Thu May 21, 2020 5:46 pm
MicroBob wrote: ↑Thu May 21, 2020 8:22 am
There were several places to collect diatomite in Oamaru area. As far as I know these usually were on private land and unimpressive in size, e.g. a bit of diatomite looking from under the grass on a cow pasture. Some of these sources will have been used up or simply bulldozered since.
I once borrowed a bottle of Oamaru diatomite and was astonished to find lots of broken shells (sometimes of very big diatoms) and very few intact frustules. So the slides one knows from Oamaru diatoms are the result of some hard work. The reputation of Oamaru diatoms probably comes from the fact that it is faily nice and diverse for a diatomite and one doesn't have to leave the house to work with it. In my view it is more worthwhile to spend the time on freshly collected diatoms.
Bob
Thanks for the insight Bob! Would you know of another particular location that provides good diversity of diatoms (fossil species for example). I've just tried my first diatom cleanup but I find at most 3-4 dominant species and occasionally the odd one out.
Two rules of thumb (the first one is scientifically valid, I think):
1. The cleaner and less polluted water reservoir, the greater the diatom diversity.
2. When carefully inspecting a strew slide, one often reveals more different forms/specie than noticed on first glance.
Rule no 1 hints that possibly, the more ancient the site, the greater the diversity.
In ornamental and man-made city small ponds and fountains, the water might be clean but diversity is small - based on limited experience.
Re: Oamaru diatomite
Posted: Thu May 21, 2020 6:57 pm
by Wes
Hobbyst46 wrote: ↑Thu May 21, 2020 6:39 pm
Wes wrote: ↑Thu May 21, 2020 5:46 pm
MicroBob wrote: ↑Thu May 21, 2020 8:22 am
There were several places to collect diatomite in Oamaru area. As far as I know these usually were on private land and unimpressive in size, e.g. a bit of diatomite looking from under the grass on a cow pasture. Some of these sources will have been used up or simply bulldozered since.
I once borrowed a bottle of Oamaru diatomite and was astonished to find lots of broken shells (sometimes of very big diatoms) and very few intact frustules. So the slides one knows from Oamaru diatoms are the result of some hard work. The reputation of Oamaru diatoms probably comes from the fact that it is faily nice and diverse for a diatomite and one doesn't have to leave the house to work with it. In my view it is more worthwhile to spend the time on freshly collected diatoms.
Bob
Thanks for the insight Bob! Would you know of another particular location that provides good diversity of diatoms (fossil species for example). I've just tried my first diatom cleanup but I find at most 3-4 dominant species and occasionally the odd one out.
Two rules of thumb (the first one is scientifically valid, I think):
1. The cleaner and less polluted water reservoir, the greater the diatom diversity.
2. When carefully inspecting a strew slide, one often reveals more different forms/specie than noticed on first glance.
Rule no 1 hints that possibly, the more ancient the site, the greater the diversity.
In ornamental and man-made city small ponds and fountains, the water might be clean but diversity is small - based on limited experience.
That fits with my observations. Do you know of a particularly noteworthy diatomite source, a given location that produces diverse fossil species?
Re: Oamaru diatomite
Posted: Thu May 21, 2020 7:58 pm
by deBult
Hi,
https://www.diatoms.nl/ Sells pre-cleaned diatom samples you can mount yourselves (plus all required mounting media and Also fully mounted slides). FOr instance he has samples from a Dutch diatom site in “Renkum” and marine fossil diatoms from several Danish sites he has visited.
May help you start doing your own slides without requiring all the aggressive chemicals.
Best, deBult (also fascinated by these little wonders)
Re: Oamaru diatomite
Posted: Thu May 21, 2020 8:07 pm
by Charles
I have found there is usually 30-40 different species of diatoms in most samples from any given site. Check the different sites I took samples from in my Diatoms post:
viewtopic.php?f=10&t=4227. I am currently working on some Oamaru diatomite given to me. It was quite a process going from 'rock' to 'clean' sample but I seemed to have quite a bit of nice frustules although there are some broken ones as well as lots of spicules, radiolaria and other debris. I'll post a picture of what I have so far.
Re: Oamaru diatomite
Posted: Thu May 21, 2020 8:23 pm
by Hobbyst46
Wes wrote: ↑Thu May 21, 2020 6:57 pm
...Do you know of a particularly noteworthy diatomite source, a given location that produces diverse fossil species?
Regretfully no; I only collect from submerged rocks and leaves, or from mud, in nearby locations. Fossil processing is too demanding.
Re: Oamaru diatomite
Posted: Thu May 21, 2020 8:46 pm
by Charles
Here are some Oamaru shots of my strew and keeper slide taken with a B&L SZ7.
Strew slide at 50X:
- Oamaru Stew slide.jpg (61.3 KiB) Viewed 5157 times
Keeper slide at 10X:
- Oamaru keeper slide.jpg (114.71 KiB) Viewed 5157 times
Section of keeper slide at 50X:
- Oamaru keeper slide2.jpg (76.22 KiB) Viewed 5157 times
Section of keeper slide at 50X:
- Oamaru keeper slide3.jpg (82.43 KiB) Viewed 5157 times
Section of keeper slide at 50X:
- Oamaru keeper slide4.jpg (82.1 KiB) Viewed 5157 times
Re: Oamaru diatomite
Posted: Thu May 21, 2020 8:48 pm
by Charles
A couple more:
Section of keeper slide at 50X:
- Oamaru keeper slide5.jpg (84.72 KiB) Viewed 5157 times
Section of keeper slide or spicules and radiolaria at 50X:
- Oamaru keeper slide6.jpg (75.91 KiB) Viewed 5157 times
Re: Oamaru diatomite
Posted: Thu May 21, 2020 9:05 pm
by Charles
This is why Oamaru diatomite is so desirable and also hard to get. This sample is from a place called Allan's Farm in New Zealand. There are of course different sites with slightly different species from the different sites. I think they say most public diatomite sites there are protected. There are also diatomite deposits all around the world. They still mine diatomite for various products like filter medium.
Re: Oamaru diatomite
Posted: Thu May 21, 2020 9:55 pm
by Charles
Here is a seller on eBay who is selling diatomite form CA and NV in the US. I haven't bought any, but am thinking of buying a few different ones and see what it's like.
https://www.ebay.com/sch/m.html?_odkw=& ... +&_sacat=0
Re: Oamaru diatomite
Posted: Thu May 21, 2020 10:08 pm
by Wes
Charles, thanks for the link to your previous thread, the images and the ebay diatomite. Btw how long did it take you to put the keeper slide together?
Re: Oamaru diatomite
Posted: Thu May 21, 2020 10:26 pm
by Charles
I'm still working on this keeper slide and have gone through about 60 strew slides of 10-15 drops each. I put a drop of concentrate to a half test tube of distilled water, mix well and drop 10-12 drops on a clean slide on a slide warmer set on low. It takes about 45 minutes to go through and pick one slide.
The raw diatomite take some time to get to cleaned concentrate. In a nutshell, you add a small pebble to a tube of distilled water and go through about 15 cycles of freeze and thaw to break it up. Then through HCl and H2SO4 and some use HNO3, so cleaning diatomite is not for the faint of heart. Respect the acids and do the cleaning outside or under a fume hood.