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Assaying microcrystals


#1

Sounds interesting. Does anyone know if there is a fairly cheap way
of sending a mineral specimen off to a crystallographer and finding
out what its chemical composition is?

I asked earlier about photographing microcrystals and I thank all
those who replied including the replies on amethyst.

Let me explain more about why I am asking but first say I am just a
prospector with credit for only first year college geology. I
prospected NWT in the 60’s and I am prospecting BC now, including
the Princeton platinum region. Princeton produced only the 2nd
commercial placer platinum river in the world I have read; the other
is in Russia.

TheBullionDesk.com declared Rhenium to be a “precious metal” and the
7th. PGE on Nov. 8/07. Its price has been driven up by demand in jet
engine construction. That is also why I asked Orchid about historic
prices for amethyst. And what about historic prices for Pt itself? Or
NaCl? Or Al? Just curiosity about mineral supply/demand I guess.

OK, cut to the chase. I have discovered an ore body of low-grade Re.
The outcropping is about 100 feet x 30 feet. It is not commercial
grade but much higher than earth crust average for Re.

There are a lot of other metallics too of course. But the
MICROCRYSTALS (barely visible) flash some wonderful greens and reds
in bright sunlight. That is why I ask about microcrystals. When you
have particles the size of flour dust, how do you photograph them? At
some point I guess the crystallogrpahers work with reflection and
refraction equipment and the crystals are not really visible or
photographable.

Also, how does one send a microcrystal off to be “assayed” not for
elements but for chemical bonding and crystalline structure?

Re in nature is not found in a “native” state because it may be the
most reactive PGE. It has only one mineral I know of in nature,
discovered so far. That is ReS2, discovered in Russia in 1994. So I
may have a brand new species of mineral here. At least one other new
Platinum mineral species has been discovered near Princeton and
named.

ReB2 is lab-made and it is said to be harder than diamond but we
have discussed on Orchid if this is an artifact of cleavage, ie if
you scratch on a fault-line you get a pseudo-scratch.

What is the jewelry value in PGE minerals? There are scores of them
known already. Unlike gold, PGE’s have lots of bonds in nature.

Thus the PGE minerals may have future value not as bullion but as
new gem crystals which can be lab-grown

cc - Energy and Mines Minister Neufeld re identification of new
crystals.


#2

Peter

  1. photomicrography - gets a picture of a crystal, through the aid
    of a microscope, optically based, limit is about 900-1,100 x

  2. scanning electron microscopy, SEM, will give photos in the range
    of 900 - 6,000x magnification, and can go up to about 80,000 or so
    if all the gods smile at the same time

  3. an x-ray spectral analysis, preferably with fourier analysis,
    attached to #2 above, can give a spot quantitative assay of a single
    micro crystal.

  4. from a mining point of view, the whole specimen goes in the
    crusher, so you are really looking for the bulk assay of the entire
    specimen, elimiating the need for #2 and #3 above.

  5. #2 and #3 are complicated; do not try them at home

as always, your results may vary

warm regards
Mark Zirinsky, Denver


#3

Thank you for the feedback and also to others who replied on this
subject. Using a hobby microscope I can get magnifications in the
range described in 1) but they only give shape in 2-dimensions. The
third dimension is fuzzy at best.

Can even expensive microphotography do better? My guess is that the
answer is no. I say that because if I check mindat for example, a see
a sample of Afghanite said to be.2 mm and Kawazalite at.5 mm. But I
see no samples on mindat for crystals of say.01 mm. Let me guess that
when I hold this sample of Re ore up to bright sunlight and see those
spectacular flashes of red, green and blue, the crystals giving off
the colour are.01 mm across. I think I can see down to.1 mm with the
naked eye so I am guessing at 1/10 that for the tiny ray in bright
sunlight. In other words I do not see the crystal itself. I see the
flash.

OK, now are they perhaps Kawazalite (Bi2Te2Se2) as there is a lot of
Bi, Te and Se in the ore I have; or are they ReTe2Se2 which would be
a new as yet undiscovered mineral species as far as I can tell.

Beyond this I also prospect mountain dust which is very lean in
organic content. Why? Because I think it is just “interesting” and
also it has great economic potential here in BC for
agriculture/aquaculture supplements and fertilizers. I honestly think
this could be a multi-billion $ future industry given that BC is 2x
the area of Japan with >90% mountain and high diversity of these
deposits.

This dust is kitchen flour fine. BTW it may be a health hazard so
I’ll mention that in case anyone goes into this further. My finger
tips are still slightly swollen a year later after handling one of
these samples. Was it As? U? Other? Dust crystals can even kill as
the example given in Hannah Holmes book "The Secret Life of Dust"
reveals (great bed-time reading). Cave dwellers in Turkey breathe in
the microcrystals. They lodge in the lungs where the sharp edges
slice up and destroy attacking cells defending the human body.
Eventually they kill the human host.

The mountain dust comes from the forces of glacial grinding,
volcanoes, water, air and gravity as well as earthquakes. It is
almost
all crystalline. As you suggest in 4) it is in the crusher - but that
is a natural crusher/pulverizer.

A gross assay of elements helps only a little. We also need an assay
of microcrystals so that agriculture/aquaculture people can take this
further. One sample I have has high U content. Is the U a natural way
of introducing helpful mutagens into the food chain? Maybe, but the
chemical structure of the U crystals is also relevant. Do microscopic
creatures in land and water ingest these U crystals which then act on
the DNA?

Speaking of Te, I have lots of ore samples with Te which is only 1/3
as common as Au in the earth crust so I may also have new Te
microcrystals. How much do we know about Te? Not much. Even a tiny
quantity makes you reek of garlic and you cannot get rid of the
smell (google on that) but it may also carry long term health effects
as yet unknown. I have samples here with so much Te that if Te rises
to Au prices I am a very rich man. Right now it is “dirt cheap”. I
laugh (respectfully) when I read the story of the guy who keeps
predicting it will do just that. I imagine he has a basement full of
Te crystals, smells like garlic and has few friends.