How to ID minerals http://www.mindat.org/msgboard-100.html Mon, 30 Nov 2009 01:55:55 +0000 Phorum 5.2.8-RC1 http://www.mindat.org/forum.php?read,100,160423,161557#msg-161557 http://www.mindat.org/forum.php?read,100,160423,161557#msg-161557 Uwe Kolitsch Analytical Techniques Thu, 26 Nov 2009 18:33:32 +0000 http://www.mindat.org/forum.php?read,100,160423,161550#msg-161550 http://www.mindat.org/forum.php?read,100,160423,161550#msg-161550 Alexandra Catalina Seclaman Analytical Techniques Thu, 26 Nov 2009 17:17:46 +0000 http://www.mindat.org/forum.php?read,100,160423,161537#msg-161537 http://www.mindat.org/forum.php?read,100,160423,161537#msg-161537 Donald Peck Analytical Techniques Thu, 26 Nov 2009 16:01:47 +0000 http://www.mindat.org/forum.php?read,100,160423,161437#msg-161437 http://www.mindat.org/forum.php?read,100,160423,161437#msg-161437 www.mail-archive.com]]]> David Von Bargen Analytical Techniques Wed, 25 Nov 2009 18:53:59 +0000 http://www.mindat.org/forum.php?read,100,160423,161435#msg-161435 http://www.mindat.org/forum.php?read,100,160423,161435#msg-161435 I have found a partial solution, calibrating the mask manually (but that is very unreliable in my opinion).
So the problem still stands, if anyone has an idea feel free to express it.

And another question,how do i join the Rietveld mailing list ? I've searched the archive but found no answer, so how do i post my question? Sorry if this is a stupid question.]]> Alexandra Catalina Seclaman Analytical Techniques Wed, 25 Nov 2009 18:34:16 +0000 http://www.mindat.org/forum.php?read,100,157610,160822#msg-160822 http://www.mindat.org/forum.php?read,100,157610,160822#msg-160822 Stuart Mills Analytical Techniques Fri, 20 Nov 2009 00:14:11 +0000 http://www.mindat.org/forum.php?read,100,157610,160821#msg-160821 http://www.mindat.org/forum.php?read,100,157610,160821#msg-160821 Ryan Eagle Analytical Techniques Fri, 20 Nov 2009 00:05:44 +0000 http://www.mindat.org/forum.php?read,100,157610,160819#msg-160819 http://www.mindat.org/forum.php?read,100,157610,160819#msg-160819 Stuart Mills Analytical Techniques Thu, 19 Nov 2009 23:52:44 +0000 http://www.mindat.org/forum.php?read,100,157610,160818#msg-160818 http://www.mindat.org/forum.php?read,100,157610,160818#msg-160818 Ryan Eagle Analytical Techniques Thu, 19 Nov 2009 23:42:35 +0000 http://www.mindat.org/forum.php?read,100,157610,160817#msg-160817 http://www.mindat.org/forum.php?read,100,157610,160817#msg-160817 Stuart Mills Analytical Techniques Thu, 19 Nov 2009 23:22:08 +0000 http://www.mindat.org/forum.php?read,100,157610,160815#msg-160815 http://www.mindat.org/forum.php?read,100,157610,160815#msg-160815
This grain occurs in metapelite directly adjacent to one of the pegmatite dykes I am studying, and I would have called it uranothorite were it not for the presence of a little P, Ca and LREE (though rather close to detection), which indicates a monazite group affinity to me. It has rimmed a diagenetic pyrite, and is stacked full of little galena inclusions. I was running out of time when I found it and straight out forgot to put yttrium in the EDS analysis, which pretty much wrecks my chances of figuring out it's true composition from what I've learned in this thread so far, but I don't seem to remember it showing up very strongly. The brighnesses in the element map I have attached aren't really relative to each other either, and the Fe/Pb channels are overlapping. The composition is a little variable across the grain, so there may be domains of different composition.

Not really after a clear cut determination at this stage, I can always revisit the thin section later next year. Just chasing some opinions, it kind of looks, walks and quacks like a huttonite with minor cheralite, etc with the data i have...

Normalised EDS:

Compound %
SiO2 15.98
P2O5 4.83
CaO 1.29
FeO 2.19
La2O3 0.07*
Ce2O3 0.85*
Pr2O3 0.28*
Nd2O3 1.04
Sm2O3 0.66*
Gd2O3 0.32*
Tb2O3 0.23*
Dy2O3 0.55*
PbO 1.09
ThO2 65.55
UO3 5.07

[attachment 18744 sunnysidethmap.png]]]> Ryan Eagle Analytical Techniques Thu, 19 Nov 2009 22:41:47 +0000 http://www.mindat.org/forum.php?read,100,158740,160802#msg-160802 http://www.mindat.org/forum.php?read,100,158740,160802#msg-160802 Nate Alger Analytical Techniques Thu, 19 Nov 2009 20:46:39 +0000 http://www.mindat.org/forum.php?read,100,158740,160800#msg-160800 http://www.mindat.org/forum.php?read,100,158740,160800#msg-160800 Alexandra Catalina Seclaman Analytical Techniques Thu, 19 Nov 2009 20:29:58 +0000 http://www.mindat.org/forum.php?read,100,158740,160690#msg-160690 http://www.mindat.org/forum.php?read,100,158740,160690#msg-160690 Nate Alger Analytical Techniques Wed, 18 Nov 2009 23:26:54 +0000 http://www.mindat.org/forum.php?read,100,160423,160601#msg-160601 http://www.mindat.org/forum.php?read,100,160423,160601#msg-160601
I will forward my question there.]]> Alexandra Catalina Seclaman Analytical Techniques Wed, 18 Nov 2009 15:12:50 +0000 http://www.mindat.org/forum.php?read,100,160423,160574#msg-160574 http://www.mindat.org/forum.php?read,100,160423,160574#msg-160574 www.mail-archive.com]]]> Uwe Kolitsch Analytical Techniques Wed, 18 Nov 2009 10:59:47 +0000 http://www.mindat.org/forum.php?read,100,160423,160546#msg-160546 http://www.mindat.org/forum.php?read,100,160423,160546#msg-160546 try the XRD newsgroup: Support and use of X-ray diffraction instrumentation [XRD@jiscmail.ac.uk]]]> Ralph Bottrill Analytical Techniques Wed, 18 Nov 2009 06:09:31 +0000 http://www.mindat.org/forum.php?read,100,160423,160423#msg-160423 http://www.mindat.org/forum.php?read,100,160423,160423#msg-160423
I have done a Rietveld refinement with the help of a PANalytical X'pert Pro but the standard configuration is giving me a lot of troubles.
I am no engineer, so the inner workings of that machine are somewhat a mystery to me. I am asking if someone else has used a PANalytical for Rietveld and if you can give me a better configuration of slots, masks etc.

Please take into consideration while writing your reply that I'm still a student and I have yet a lot to learn.

Thank you!]]> Alexandra Catalina Seclaman Analytical Techniques Tue, 17 Nov 2009 08:24:24 +0000 http://www.mindat.org/forum.php?read,100,159207,160321#msg-160321 http://www.mindat.org/forum.php?read,100,159207,160321#msg-160321
I think You have to contact the Geological or Chemical Department of an university. But I have no idea, how much this costs.

Greetings from Goslar

Georg]]> Georg Graf Analytical Techniques Mon, 16 Nov 2009 09:48:38 +0000 http://www.mindat.org/forum.php?read,100,151910,160032#msg-160032 http://www.mindat.org/forum.php?read,100,151910,160032#msg-160032
The isotopically purified carbon you refer to is essentially pure carbon-12 in other words we are talking about carbon-13 depleted. Natural carbon is approx 99% C-12 and the rest mostly C-13 (and tiny amounts of the radioactive C-14). Yes the C-13 depleted diamond acts like you say and in addition it has markedly superior laser properties (quantum mechanical arguments) over regular diamond.

Back to thermal conductivity. Think about heat as atomic motion. Conductivity is due to atoms hitting neighbors and passing on motion to them on the whole going from high temperature to low. Not only does diamond have a lot of atoms per unit volume but in any diamond the atoms are all bonded together in a strong tetrahedral arrangement, a diamond is essentially a SINGLE molecule! The strong 3D structure accounts for extreme hardness. As for the electrical insulator properties? All its electrons are tied up unlike metals or graphite so no electrical conductivity.]]> John Attard Analytical Techniques Fri, 13 Nov 2009 04:34:06 +0000 http://www.mindat.org/forum.php?read,100,155087,159678#msg-159678 http://www.mindat.org/forum.php?read,100,155087,159678#msg-159678
A friend of mine has been assisting with the software for what is currently described as a multi-shot Raman Spectrometer, where a single "point" is targeted with different laser frequencies in sequence. With careful calibration, I gather that the early results are promising, even using using a prototype with commercial 720nm (deep infrared), 640nm ("ruby" red) and an unspecified blue laser (I guess that they're scavenging from Blu-ray^(TM) disc drives).

Unfortunately, the processing still requires some fairly sophisticated equipment, so a laptop computer is essential if you want to take even basic Raman equipment into the field.

At the end of the day, the accuracy of Raman Spectrometry relies on several factors:

Sensitivity and discrimination of the detector
Signal quality (both optical and electronic)
Intensity and coherence of the laser
Area of the sample site
Calibration and drift of the equipment
Quality and applicability of the analytical database

This field is still in its infancy (it took about 60 years for XRD to reach maturity), so it may be a few years yet before a reliable, portable and (relatively) inexpensive device is widely available.

Incidentally, I certainly wouldn't want a hand-held XRD setup for frequent use, but field-portable equipment is already available. X-Ray sources in close proximity with body parts are definitely not desirable.]]> Alysson Rowan Analytical Techniques Tue, 10 Nov 2009 15:55:20 +0000 http://www.mindat.org/forum.php?read,100,158740,159615#msg-159615 http://www.mindat.org/forum.php?read,100,158740,159615#msg-159615
I have done a lot of X-ray spectrometry on rocks in lithium tetraborate fusion discs. Our instrument was admittedly a pretty heavy duty tube excited instrument that produced a strong X-ray flux. But I used to be able to tell if my samples had been analyzed yet just by looking at them. If they had already been irradiated the disc would be discolored brownish/gray (and that was after only 100 seconds. Years ago I put a piece of fluorite in the spectrometer and was surprised when its color changed to bright purple. I laid the sample on the lab bench, and by the next day the purple color was gone and the sample was ugly gray. I have no idea how strong an X-ray flux your instrument produces, but if you still want to experiment with the machine, I would suggest you try a small cheap scrap sample of your gemstones that you can afford to have turn off-color. Better to put an unfaceted scrap in the machine than ruin a finished gem.]]> Joseph Taggart, Jr. Analytical Techniques Tue, 10 Nov 2009 01:42:42 +0000 http://www.mindat.org/forum.php?read,100,159207,159207#msg-159207 http://www.mindat.org/forum.php?read,100,159207,159207#msg-159207
I m looking for some lab performing lead isotope studies (ICP-MS with magnetic sectors?). We would like to date source of hydrothermal mineralization where only mineral suitable for dating is galena. I know this technique is a little bit out-of-date, but we have no uraninite, zircones, monazites, feldspars etc. I will be grateful for any advice.

Thanks.]]> Jakub Jirásek Analytical Techniques Sat, 07 Nov 2009 19:00:22 +0000 http://www.mindat.org/forum.php?read,100,158740,158785#msg-158785 http://www.mindat.org/forum.php?read,100,158740,158785#msg-158785 Pavel Kartashov Analytical Techniques Thu, 05 Nov 2009 01:56:29 +0000 http://www.mindat.org/forum.php?read,100,158740,158777#msg-158777 http://www.mindat.org/forum.php?read,100,158740,158777#msg-158777 Nate Alger Analytical Techniques Thu, 05 Nov 2009 00:45:04 +0000 http://www.mindat.org/forum.php?read,100,158740,158769#msg-158769 http://www.mindat.org/forum.php?read,100,158740,158769#msg-158769 Pavel Kartashov Analytical Techniques Wed, 04 Nov 2009 23:23:25 +0000 http://www.mindat.org/forum.php?read,100,158740,158745#msg-158745 http://www.mindat.org/forum.php?read,100,158740,158745#msg-158745 Nate Alger Analytical Techniques Wed, 04 Nov 2009 19:28:51 +0000 http://www.mindat.org/forum.php?read,100,158740,158740#msg-158740 http://www.mindat.org/forum.php?read,100,158740,158740#msg-158740 I have access to an X-ray spectrometer which is generally used to test metal fineness and rhodium thickness etc. My question is whether this machine has any application in testing gemstones, for instance if I put a sapphire down on the eye and the machine showed Be is present would this be a reliable way to asess treatment with beryllium? Is there any software that is compatible with this machine that focuses more on gems than metal?? Any assistance would be greatly appreciated, thanks!!]]> Nate Alger Analytical Techniques Wed, 04 Nov 2009 19:17:19 +0000 http://www.mindat.org/forum.php?read,100,157610,157713#msg-157713 http://www.mindat.org/forum.php?read,100,157610,157713#msg-157713 Ryan Eagle Analytical Techniques Mon, 26 Oct 2009 10:21:11 +0000 http://www.mindat.org/forum.php?read,100,157610,157699#msg-157699 http://www.mindat.org/forum.php?read,100,157610,157699#msg-157699
"Divided Wt% elements by atomic number, giving relative mol amounts (I doubt this is quite right, can't be this easy)"

It's almost that easy. You must divide wt% by atomic mass, not atomic number.]]> Tomas Husdal Analytical Techniques Mon, 26 Oct 2009 08:19:09 +0000