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 Post subject: Diagnostic differences
PostPosted: Mon Nov 14, 2005 6:15 pm 
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Could we start a thread about diagnostic differences between look-a-likes to make things easier for students?

Like Topaz and Tourmaline falling in the 1.61-164 RI range but have totally different DR's and SG's.
Also the new clinohumite falls in that range.

Well you get my drift .. it's blue and double reftractive, but you can easily scratch indicolite because indicolite isn't biaxial.


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 Post subject: Wow, this would be Great
PostPosted: Mon Nov 14, 2005 7:37 pm 
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Doos,

I would love to get more information from all the pros out there on this. It is very hard to learn when you are isolated as I am from other students. This is a great place to learn from the experts. I will not be able to have any input, but I will be here every day looking for new postings and will follow with the group as we learn from experts. I may even ask some questions if it gets over my head if that is ok.... Carl the Gemlover.....


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 Post subject:
PostPosted: Tue Nov 15, 2005 1:15 am 
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That is a great idea Doos.


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PostPosted: Tue Nov 15, 2005 11:12 pm 
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I think this discussion is valuable to everyone! Students and professionals. Thank you Doos for thinking of it!


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 Post subject: The dichotomy of gems
PostPosted: Wed Nov 16, 2005 8:58 am 
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This type of deductive elimination is called a dichotomous key (or identitication key) in biology, and it can indeed be very useful, especially when trying to sort several highly similar specimens into genera and species. A gemmologist can certainly adopt this method. The data can be arranged into a graphical schema, namely a flowchart, and this can serve both as a reference tool and a study exercise.

Such a key could be organized either by colour (probably the most practical), or for the more mineralogically inclined, by class (silicate, carbonate, oxide, phosphate, halide, etc.). It would be a lot of work to compile a complete key for all 150+ minerals fashioned into gemstones, but an abridged version covering the most common ones might be something worth spending a few weekends on.

As an aside, this forum's description contains two orthographic errors:
The Forum wrote:
Diagnostic Clues: How the pro's seperate gems whose properties overlap to the point of utter confusion!

Bolding mine: there shouldn't be an apostrophe in "pros", and sepArate is misspelt. Sorry to bring this up here, but I didn't know who I should bug with a PM. Cheers.


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 Post subject:
PostPosted: Wed Nov 16, 2005 9:17 am 
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What's "A comma" between friends anyways? :lol:

Snizzy and Barbra are the two people here who have respectively moderator and administrator status, so anything like that should be directed to either of these ladies.


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 Post subject: Re: The dichotomy of gems
PostPosted: Wed Nov 16, 2005 12:08 pm 
Gregory wrote:
(or identitication key)

As an aside, this forum's description contains two orthographic errors:
The Forum wrote:
Diagnostic Clues: How the pro's seperate gems whose properties overlap to the point of utter confusion!

Bolding mine: there shouldn't be an apostrophe in "pros", and sepArate is misspelt. Sorry to bring this up here, but I didn't know who I should bug with a PM. Cheers.


LOL! We don't take points off for spelling Gregory! And it's a good thing considering the misspelling of "identification" above. 8)


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PostPosted: Wed Nov 16, 2005 12:15 pm 
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Good grief.
Thanks Gregory for your help.
Sometimes I type too fast and don't proof read.....and sometimes I'm just stupid.
You can always feel free to correct my spelling, although I do suspect it may be a full time job.

Thanks Snizzy, for finding Gregory's spelling error...I totally overlooked it.


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 Post subject:
PostPosted: Wed Nov 16, 2005 12:18 pm 
LOL! I always overlook spelling errors, but I couldn't resist the irony of that one! :wink:


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 Post subject: Key
PostPosted: Wed Nov 16, 2005 1:50 pm 
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Gregory -

The same thing popped into my mind - a key, or critical path, or whatever the heck it's called. [Dang, I hate it when the needed memory cells are asleep at the switch...] We've all seen those tree-diagrams with "Yes" and "No" boxes...on IRS forms, if nothing else.

Isn't there some piece of gemology software from Adamas that does this? Has anyone tried it? What is the starting parameter - something simple like color, or something a bit trickier, like refractive index?

Staying tuned,
Chris


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 Post subject:
PostPosted: Wed Nov 16, 2005 2:00 pm 
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The software most suitable for this is your own brain. No programme can ever compete with that on this topic (atleast not for now). It's the associative memory that makes us superior over computers.


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 Post subject: Skitt's law
PostPosted: Wed Nov 16, 2005 11:52 pm 
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Snizzy wrote:
LOL! We don't take points off for spelling Gregory! And it's a good thing considering the misspelling of "identification" above. 8)

You're quite right; I've fallen victim to Skitt's law, as I was no doubt destined to. This is why I usually suppress my inner Grammar Harpy, unless the error is particularly important; such as one that mars the forum index's Junoesque facade. ;)


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 Post subject:
PostPosted: Thu Nov 17, 2005 12:43 am 
Thanks for sharing Skitt's Law, Gregory - that is hilarous!!

You've got to admit the whole incident is quite amusing. :lol:

And don't worry - you can PM me or Barbra anytime you detect a spelling or gramatical error and we will be glad to correct it.

BTW - Do you really think the Junoesque appearance of our forum index is merely a facade? :wink:


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 Post subject: What?
PostPosted: Thu Nov 17, 2005 2:16 pm 
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Thank you ALL for making me run to the dictionary every few postings to know what you are talking about. Everyday you can learn something new is a wonderful day...... and again my friends, you made today a wonderful day.


Carl the Gemlover :D


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PostPosted: Thu Nov 17, 2005 3:18 pm 
Glad to hear you are having a wonderful day Carl, and that we can be part of it!

You'd better keep your dictionary handy! I think Gregory is a bit of a "wordsmith"who will keep us all on our toes!


Gregory - is "wordsmith" even a word? :wink:


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