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 Post subject: spectroscopes; the end is near?
PostPosted: Sat Jan 10, 2009 3:49 am 
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Ah, it is the spring semester of the odd year, my favorite time. Students doing lots of interesting things in lab. I love the smell of solder in the afternoon. Smells like... victory.

However, seems a bit quiet in this forum, so I thought I'd stir the muck.

For some reason, some time ago I developed an interest in spectroscopes. So I searched the internets to locate who actually uses them. What I found is that, basically, only gemologists use them. Which is good, in a way, because I found this interesting forum.

However spectroscopes are old, 19th century, technology. How long can their use in gemology be sustained? How long will it be before their use in gemology succumbs to the fate of their use in forecasting the weather?

Nowadays, there is a 21st century technology poised to replace the spectroscope. There is no standard name, but those in the know, know what I'm talking about. Digital spectrometers that can produce plots of transmission intensity vs. wavelength. Although Ocean Optics is the market leader in this technology, there are many other companies producing similar technology. To save typing, let's invent a nomenclature for this technology: digital spectrometers that produce digital spectra plots.

I believe, if gemology exists in fifty years, then every gemologist kit will include digital spectrometers. By that time, spectroscopes will have been replaced completely by these instruments. However, not being in the field, I'm wondering what people's opinion of when the tipping point will occur. For example, when will the gemology teaching institutions incorporate these instruments into their curriculum?

Let's use the "generation" marker... it takes roughly 20 years to evolve a new generation. Will the tipping point occur in 1/2 a generation? Will it occur sooner? Will it occur later?

As food for thought, I will go out on a limb and list the pros and cons for replacing spectroscopes with digital spectrometers that I can think of.

Pros:

We can see by recent thread and another recent thread that out of the repertoire of gemology instruments, the spectroscope is the one that gives most trouble. Its results depend on the human eye, whose sensitivity across the spectrum is variable, to say the least.

Couple eye variability with a variabilty in the light source used to view the spectrum produced by a gem, and one finds a very sticky wicket. In fact, one can easily be misled by the environmental light source.

In contrast, digital spectrometers are calibrated for flat response across the spectrum, and they can divide away the effects due to the light source used. So that, given the same stone, two investigators located a hemisphere away, using different light sources, should end up with essentially the same digital spectrum.

Also, spectrometers producing digital spectra plots are becoming a commonplace tool in high school science labs. I teach college students how to use spectroscopes, and how to use digital spectrometers. Personal experience says the latter is much easier to teach... point and shoot, rather than example after example after example to see what to look for. I've handed my best spectroscope to people visiting my office, had them look at the sky... they never see the Fraunhofer lines until I point them out. In contrast, these lines appear readily in a digital spectrum.

One can complain that one needs to connect the digital spectrometers to a computer to collect digital spectra graphs, but that is so not true. At the high school level, calculator-sized instruments can be used to record, save, send on, or display the spectra.

Lastly, the digital spectrometers can extend the wavelength range well beyond the visual spectroscope. The spectroscope covers the visual range of 400-700 nm, whereas nowadays it is easy to find a digital spectrometer that covers the 200-1100 nm range. Thus, the digital spectrometer increases the wavelength range by a factor of 3! More range gives more features to identify. In my own particular investigations, Jean-Marie commented in passing about a certain absorption feature in the infrared that should appear in beryls. Then John reminded me of this feature, and I verified its appearance in beryls. It seems to me that the occurrence of this feature, appearing beyond the visual range, adds strong evidence to a verification of some material as beryl.

Next we examine cons:

At the current time, putting together a basic digital spectrometer and a hand-held acquisition and display tool will cost around $2000. If you already have a computer and shop around carefully, you can get state-of-the-art spectrometer (nod to alberto :wink: ) for half that cost. In contrast, the ultimate OPL spectroscope costs a bit more than $100.

My contrapoint is that gemologists pay a lot for a microscope. And I recall that when basic calculators were first introduced in the early '70s, they cost a hundred $ or more. Only a decade later, you could get freebie calculators from drug reps and the like, which means they must have cost pennies to produce and cost around a dollar retail. In a similar manner, as the secondary market opens, we should see a decrease in the cost of digital spectrometers over the next decade.

A second accusation that could be made is that gemologists are not "math" people, or more specifically, they do not want to learn "how to read graphs".

My contrapoint is firstly, given a strong enough reason, anyone can and will learn any aspect of math they absolutely have to. If it is part of a curriculum, students will learn it. Secondly, jeez, gemmos learn the wavelength scale, which is the much more difficult half of reading a spectral plot.

A third difficulty I see is that people have no idea how simple it can be to collect digital spectra. I can see an opening in the market for developing a standard platform for holding the gem and light source, then point the optical fiber from your digital spectrometer, and collect. After my own experimentation, I can see this is not so difficult to do... Maybe someone could make some money (we academics have some problem with our DNA, in that we willfully ignore money-making opportunities).

Another difficulty I see is that, although the spectroscope is old technology, it has only recently been applied to gemology. This suggest that gemology has functioned quite well without it. To put it another way, the spectroscope is not a primary go-to instrument, like the loupe or microscope, SG, and RI measurement instruments. Maybe the late arrival of the spectroscope to gemology studies forebodes a similar late arrival of the digital spectrometer.

These are my first couple thoughts on pros and cons. Maybe all this isn't well thought out, but I decided to throw it out anyways. So what say you?...

...When will the spectroscope be replaced by the digital spectrometer as a commonplace tool in the repertoire of gemology? When will actual digital plots of spectra replace "line designations" determined with the spectroscope? What holds back the use of digital spectrometers? What encourages the continued use of spectroscopes?


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PostPosted: Sat Jan 10, 2009 6:33 am 
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As soon as spectrometers become affordable (a grand sounds great!) they'll find their ways into personal gemmo labs. (nod to Alberto, our pioneer :D ). I'm quit sure that I'll never chuck out my spectroscope though... Their use in the field is indispensable.
Certainly I'm looking forward to the days Raman set-ups, UV-Vis, FTIR, XRF, EDXRF spectrometers etc appear on ebay without a reserve and a 99 cents starting bid...

I taste the same thing I felt among other 'new graduates' of gemmology: "we could have learned more..." I think the gemmo schools' curriculum upgrades are overdue. I would have loved an in depth 'digital gemmology' chapter.

EDIT:
Heck, information isn't just information when it requires paying for... Free is even better... Let's start a new chapter here on the forum regarding advanced gem testing. I'm thinking general info & databank of collected data.


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PostPosted: Sat Jan 10, 2009 10:15 am 
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Hi Dr. Brian,

I’m very glad you raised the issue and, let me thank you again for the support.
I’m started interesting about spectrometers in last years cos i noticed the development of new devices, smaller but, and this is the main factor, extremely cheaper than the older big boxes.
To have an idea of what I mean you need only to have e look on ebay. There you’ll find a lot of big boxes, buyed for new not more than a decade ago for 20-30-50k or more which now stands at few thousands, in many case unsold. The key factor is that, nowadays many manufacturers (Ocean Optics, Avantes and others) build more versatile micro spectrometers which don’t have the built-in computer or other electronics which can rapidly became obsolete. Although I think 2k is a little bit optimistic quote for an entry level complete setup (I would say at least 4-5k), we are talking however about a fraction of how much was needed only few years ago.
We all Know gemology instruments are produced by few manufacturers cos the “market” is a really little niche to have real competition. This is the main reason why many gemmo devices are pratically the same of old one except for some fancy external restyling, R&D costs too much compared to the profit.
But back to spectrometers.
I Think it can be VERY useful nowadays to have a detailed spectrum of a stone in order to detect important features which are, for example in many cases distinctive for treatments.
The main problem is about the total lack of sources for comparative spectrum analysis. It would be great to have something like the RRUFF project for UV-VIS-IR, unfortunately I didn’t found nothing similar. But something is moving about the issue. SSEFpublished in the n15 newsletter called facette (it’s a pdf file which can be downloaded in SSEF site) an article about a relatively cheap complete spectro setup developed for gemologist. I’ve requested more infos and they kindly sent me a more detailed pdf about the setup (I saved a copy if someone is interested). For what i saw it’s a good setup based on 2048 pixel Avantes spectrometer. The more interesting part is the dedicated software (or spectra database?) developed for gemmo purpose exclusively. But this have a cost. The setup price is 20k CHF which means, more or less 18k US$. You can say it’s too much but, however there’s no competition in this field right now. IGI antwerp laboratory made a connection with Avantes in order to enter this market, but I have no more clue than you can read in their webpage.
Hopefully other labs (GIA, Gubelin etc) will do in the future the same and maybe prices will drop more even if i’m a little bit skeptical about that.

Back to your questions,
Brian wrote:
...When will the spectroscope be replaced by the digital spectrometer as a commonplace tool in the repertoire of gemology? When will actual digital plots of spectra replace "line designations" determined with the spectroscope? What holds back the use of digital spectrometers?

IMHO

When they will be cheaper
When their use will be covered in gemological courses
When significant sources for spectra database/libraries will be available
When there will be more specific publications about the issue available.


Tim Spauwen FGA wrote:
Let's start a new chapter here on the forum regarding advanced gem testing. I'm thinking general info & databank of collected data.


That would be really GREAT! I’ll be for sure one of the contributors when my setup will be ready. (Right now Gene is working on that, thx Pal :wink:)

Ciao
alberto

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PostPosted: Sat Jan 10, 2009 2:08 pm 
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RAVIRUS wrote:
The main problem is about the total lack of sources for comparative spectrum analysis.

Before I ever got to your comment, that was my exact thought as well Alberto.

Brian, I think it's time for you to write your book. :smt115

Regarding Alberto's other comments:

RAVIRUS wrote:
When they will be cheaper

I'd gladly pay the current cost for an entry level unit just to start getting experience if the reference material was available. Oh Brian.... ;)

RAVIRUS wrote:
When their use will be covered in gemological courses

Anytime business meets academia you're in for problems. The courses most likely won't contain the information until they're being used by gemologists, and gemologists will be slow to incorporate them until it's taught in the courses. Until then, those who have a passion for this field will be the only ones to find the units and learn how to use them.

RAVIRUS wrote:
When significant sources for spectra database/libraries will be available
When there will be more specific publications about the issue available.

THIS is what is currently needed.

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PostPosted: Sat Jan 10, 2009 2:18 pm 
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MacGyver wrote:
Brian, I think it's time for you to write your book. :smt115


if this is a sort of petition, well, where i have to sign? :mrgreen:
kidding aside i think this could be the right moment for a BRAIN (Brian?) to write what we really needs: an updated version of the spectroscopy and gemology book, maybe focused on the use of modern spectrometers completed by a spectras library. i'm more than sure it could be a best seller! (gemologically speaking, of course :wink: )
ciao
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PostPosted: Sat Jan 10, 2009 2:23 pm 
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Please make it a "Spectometers for Dummies" book! :oops:

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PostPosted: Sat Jan 10, 2009 3:12 pm 
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I am not very techy, but had occasion to use a little Ocean Optics unit for a while. I think if you write the book you might find there is a bigger market than you might think.

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PostPosted: Sat Jan 10, 2009 3:27 pm 
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John Fitzgerald wrote:
I am not very techy, but had occasion to use a little Ocean Optics unit for a while. I think if you write the book you might find there is a bigger market than you might think.


If enough of us inquired, you might even find Ocean would license the book for sales purposes. BTW, where do I preorder my copy? ;)

John, having seen the other version of that comment for years, I freakin LOVE you're sigline. Image

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PostPosted: Sat Jan 10, 2009 7:16 pm 
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John Fitzgerald wrote:
I think if you write the book you might find there is a bigger market than you might think.


not so sure about that. i guess the percentage of units sold for gemmo purpose don't reach 1% of the whole. but, well, maybe i'm wrong.

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PostPosted: Sat Jan 10, 2009 7:41 pm 
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It really does come down to supply and demand. Science is sometimes limited by need. Not so much can it be done, but, who needs it and is there profit and sustainability in it. Who will take the risks and pay the costs?
How much interest was there in my "Interesting Study" thread before this? Is there enough financial interest to make it a viable product?

Maybe Gemologists need Telethons. It's worked for Jerry Lewis. A lot of money invested/donated with less than spectacular results. A noble cause none the less.

Big world, many problems, limited resources.


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PostPosted: Sun Jan 11, 2009 1:18 am 
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I believe the spectroscope was originally promoted by Basil Anderson. One day at lunch, after I had sent one of my instruments to him to evaluate, he suggested my greatest contribution to gemology could be for me to take it off the market. I did. Later he also endorsed the OPL.
He also confided that the reason he adopted the spectroscope was that he was color blind.

Basically, gemological spectroscopy is simply a matter of pattern recognition. zircon, ruby, sapphire, emerald, garnets, etc. all have spectra which can be recognized on sight. These are the major stones of interest to commerce and one doesn't need more than an OPL. The rest are of little interest except to gemophiles and researchers. Consequently, I believe the market will remain small for a long time. Which brings to mind one of my favorite sayings, "If a thing is not worth doing at all, it is not worth doing well." :D :D


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PostPosted: Sun Jan 11, 2009 1:47 am 
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I am a HUGE fan of the optical / OPL type spectroscope. It is my primary instrument I use, ( since I don't have shiny facets BEFORE i buy rough).. and have spent many hours learning to use it..

I agree w/ Dr. H. here and think, like learning your multiplication tables, folks should learn how to use a hand held unit, because then, it will make a digital unit so much more easy to understand and use correctly.

The digital Refractometer I invented but never built, had an upgrade path for a cheap digital spectroscope as well. So I got to look at this a bit as well..

Here are a couple of the advantages of a digital spectroscope that folks might not be aware of..

- Broader light sensitivity. Because the digital chip output can be processed, you can see faint artifacts in the absorption/emission lines as well as the stronger ones. (quantitative analysis)

- Image processing capabilities. Can resolve lines that are merged or not readily apparent. (resolution and edge sharpening)

- UV/ IR properties. As Brian alluded, we can see items in the higher/lower order spectrums that can be distinctive. (extended range)

- Automated pattern matching. Back in the 80's I wrote the software for a self training neural networked based pattern classifier for OCR on the macintosh. Stroke analysis eventually won out, but with a finite set of spectra, that methodology could easily be used to create a rank order of ID based upon best fit

Didn't someone here mention something ( Maybe it was you Dr. Bill) about using a cheap digital web cam as a ghetto spectrascope?

I just got a Mac and will set it up shortly for I-Phone dev apps. Would love to hook a cheap ghetto spectrascope up to an Iphone and capture the imagery.. Hey. if someone can make 1.5 million in 3 days selling a flatulence ringtone in the I-phone app store.. maybe there is a market :lol:

Back to Brian's thoughtful thread.. Lots of really good instrumentation goes into the gutter as "slicker" gets written up in the journal articles and replication requires the Latest Greatest HYPERDRIVE Black Hole Nuclear Magnetic Resonance Spectrometer (complete with 20 ton crane to lower it onto the reinforced concrete lap through the hole in the lab roof). While a very nice FT-IR Spectrometer can do a nice job of chemical structures as well. Or my favorite.. Thin Layer Chromatograpy (costs $1.50 a test, do it in your kitchen) vs buying a $30,000 Gas Chromatograph from Agilent.

Well, at least if we get a hand held iphone version ( I like the idea of quick field use) then I can color the grey scale in w/ the right colors!

Anyone ever post anything on how to photograph spectra through an OPL ?? or did someone say that can't work?

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PostPosted: Sun Jan 11, 2009 12:26 pm 
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pardon my ignorance, but as I have so much I thought I would share . . .

I have a Vreeland Spectroscope 7 with the consumable bits, and a Dage MTI CCD 72 camera; unfortunately not yet setup due to a lack of space/venting. Why would the results of such using powdered rough not be suitable for defining the expected spectra? (FWIW, that is certainly what I bought it for - along with mineral specimens.)

Anyone here have experience actually using the Vreeland, I know Gene has one.

Bill


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PostPosted: Sun Jan 11, 2009 3:17 pm 
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Sadly, I do not feel the average gemologist (which includes myself) is anywhere near being qualified to interpret the data collected by sophisticated spectographic units.
One would need a very advanced mineralogical background so that the data would be correctly understood. It is foolhardy to presume that a layman could compare findings to some series of charts and think that correctly identifies much of anything.

I think gemological schools should all offer facilities for advanced training. I'm not sure what Gem-A is offering is even enough.


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PostPosted: Sun Jan 11, 2009 5:05 pm 
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Barbra Voltaire wrote:
Sadly, I do not feel the average gemologist (which includes myself) is anywhere near being qualified to interpret the data collected by sophisticated spectographic units.


hi Barbra,
i think nobody here said an average gemologist can use a complex unit with no scientific background. We are talking about simple uv-vis-nir units which can collect spectrum more precisely than a spectroscope can do.
i guess, i'm sure you have many spectrum charts to compare your spectroscope reading. whats wrong to have a more precise instrument and a spectras databank to made the same?
ciao
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