General EPMA > EPMA Standard Materials

An Open Letter to the Microanalysis Community

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crystalgrower:
RESEARCH quantities of many materials were grown by national labs, after funding defined the possible or expected military or aerospace applications.  Research quantities were +/- 100 grams per batch.   Batch to batch variations from flux are common.  Single crystals would never be possible from fusion of a gel or other simple prep.

This means NOT ALL materials and NOWHERE NEAR the kilogram goal of the new collection.    It also means BATCH TO BATCH VARIATIONS  as opposed to the "unlimited" commercial prep of POWDERS.  A stated goal of the new collection was to avoid "flyspeck" mounts--that means that this becomes a series of custom syntheses of multiple batches.

The number of experienced crystal growers in both public posts and the pdf attachments runs about 1% of the responders.  We have all posted far higher costs and minimum equipment requirements for one reason--we actually know how difficult it is to grow a 1mm sized single crystal of a material that does not undergo a phase change during growth.

My own years of work have been summarized by a user as "secret sauce" https://probesoftware.com/smf/index.php?topic=1520.0  This is actually more polite than many offensive in-house emails that accused me of "just making work" while crystal production was being optimized. 

My final point is this: that perfect record keeping is also more important than anybody thinks.  I am the only person who is willing to admit that I kept a legal copy of some Astimex records.  Astimex Standards stopped answering calls and emails sometime in 2018.  HOW do future collections plan to prevent this dead airspace?

Probeman:

--- Quote from: crystalgrower on April 28, 2023, 09:03:29 AM ---RESEARCH quantities of many materials were grown by national labs, after funding defined the possible or expected military or aerospace applications.  Research quantities were +/- 100 grams per batch.   

--- End quote ---

If we distributed mounts with 500 milligrams of material each, that would still be enough material for 200 microanalysis laboratories.  That's a good start for global distribution set!

How can we locate these "hoards" of single (or poly) crystal material?  We need to talk to these people and find out what they know. I have heard rumors that many such experiments in various national labs in the US, China and Russia produced large quantities of material, but the trick is locating these "buried treasures".

Especially materials which are evidently not currently produced commercially.  A few such materials would be of great interest to us in the microanalysis world are listed here:


--- Quote ---ZrSiO4 (zircon), ZrO2 (zirconia), HfO2 (halfnia), ThSiO4 (tetragonal thorite), ThSiO4 (monoclinic huttonite), Fe2SiO4 (fayalite), Mn2SiO4 (tephroite), CaMgSi2O6 (diopside), Al2SiO5 (sillimanite), NaAlSiO4 (nepheline), KalSi3O8 (sanidione), KAlSi2O6 (leucite), KAlSi3O8 (orthoclase), NaAlSi3O8 (albite), CaAl2Si2O8 (anorthite), Fe3Al2Si3O12 (almandine), PbSiO3 (alamosite), CaAl2O4 (krotite), CaAl4O7 (grossite), HfSiO4 (hafnon), CaAl12O19 (hibonite), CaSiO3 (wollastonite), MgSiO3 (enstatite), FeSiO3 (ferrosilite).

--- End quote ---

Please read Dale Newbury's message quoted here for more details:

https://probesoftware.com/smf/index.php?topic=1415.msg11754#msg11754

crystalgrower:
A mount with 500mg is 10X more than what had been very widely sold in the past.

Labs do not use large-item mounts in routine work because they take up too much space.  Many labs have filled corners and interstices between 25mm holes with 10mm mounts.
Charles Taylor started cutting materials into 2 x 2 x 2mm cubes which works out to 0.008cc or  20-50mg of material. I guess there would be some waste for cutting.  You can mount at least 40 of these into a 25mm circle.  Taylor used drilled steel cups (expensive)  and Rucklidge used brass rings.   Both mount styles have a working life of 40+ years depending on the care.

 Public Appeals

The pandemic closed down the personal contacts at major meetings of MSA (mineralogists)  and  ACS and AGU. The old stashes, if they still exist, will be found by direct contacts. 
Access to foreign collections means asking for help from people who can read Russian or Chinese and who have time to trawl through google.   

A letter in Elements Magazine would reach some of the  Asian member groups. 

A special Elements issue on the comprehensive subject of EPMA history and calibration might be useful but it will take 2 years to get off the ground.   This is where you write an article asking for global participation in the k-values project. 

The Taylor and Astimex stashes were handed over by Rucklidge to Mike Gorton who is still listed at the University of Toronto.  The Taylor stash had plenty of YAG, SIO2, Al2O3, and synthetic pyroxenes and spinels.   Also exceptional minerals like Foord spessartine and Rucklidge Batbjerg Cr-diopside.  The simplest compounds were stockpiled for working standard mounts because they represented the highest concentration possible. 

There are also cases of “too little too late”. 

There was a commercial outfit with large volume hydrothermal systems for producing synthetic minerals.  They got SBIR grants in 2006 and 2008 and were out of business before 2015.  They would have been the ideal outfit to replace Pb-contaminated monazites using the high-efficiency process published in 2003.

Dorian Smith who had some supply of synthetic spinels (CoAl2O4 etc)  died in 2013 after which his company Micronex shut down. 

And of course REE.

You need REE phosphates  for the SEM-SDD-EDS that is the new fast sensitive screening  analysis.  Neither the Drake or Edinburgh REE glasses are optimal.  Never mind that the process for the Edinburgh glass was published--useful details are missing.  But the Si-Al matrix is a waste of time for REE.

SO—Nobody has bought my orthorhombic  RP5O14 for a decade.  I am in a position to start  production of  mixed phosphate crystals to replace Si-Al REE glasses. Hydrothermal  monazite is a really good matrix for mixed cations.  But there is no reason to think that anybody will accept it from me.

Probeman:

--- Quote from: crystalgrower on May 29, 2023, 09:06:46 AM ---A mount with 500mg is 10X more than what had been very widely sold in the past.

--- End quote ---

Yes, exactly my point. Even if we could produce only 100 grams of each material, we'd still have plenty of material to distribute to every microanalysis lab in the world.  It's also not a bad idea to have a reserve of material set aside for future mount production.


--- Quote from: crystalgrower on May 29, 2023, 09:06:46 AM ---The pandemic closed down the personal contacts at major meetings of MSA (mineralogists)  and  ACS and AGU. The old stashes, if they still exist, will be found by direct contacts. 

Access to foreign collections means asking for help from people who can read Russian or Chinese and who have time to trawl through google.   

A letter in Elements Magazine would reach some of the  Asian member groups. 

--- End quote ---

I'm giving a talk to a Chinese EPMA group this week and I will make that appeal directly to them.  A letter in Elements magazine is a good idea.

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