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 Post subject: Equipment for beginners - Rough gems screening
PostPosted: Fri May 23, 2014 2:15 pm 
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Joined: Fri May 16, 2014 6:23 am
Posts: 10
Dear All,

My question about equipement needs is restricted to rough stones (I focus on diamonds, emeralds, sapphires and rubies only).
After having read many threads here, I finally bought a Belomo triplet and a Tanita 1230 (portable one).
What additional pieces of equipment do I need to accurately differentiate a fake within a set of real precious stones?
Which methodology should I follow / other equipments I shall buy to have a quick & dirty appraisal?

Thank you in advance for your help

PS: I will not buy on my own rookie opinion only but I would love to have some independant point of view and be able to challenge in charge gemologist ;)


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 Post subject: Re: Equipment for beginners - Rough gems screening
PostPosted: Sat May 24, 2014 4:12 am 
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Joined: Tue Dec 17, 2013 3:50 am
Posts: 25
Hi,

It's a short question with several long answers.............If you're new to this, you might want to think about some education rather than just focusing on equipment. If you understand the mineral crystal systems and something about surface features of natural crystals under magnification, you'll be able to tell a lot more with your loupe if the stones aren't water worn (or tumbled to look water worn). Likewise if you understand a little about how gems interact with light you'll be able to decide for yourself which "quick and dirty" tests you want to do on a particular stone, and which piece of equipment you'll need to do the test with. I think it's helpful to understand how your equipment works too, so that you know where likely sources of ambiguity are! Also, if you are a little familiar with the science, you'll be more likely to be able to rig up a quick test "on the fly" with whatever tools you have to hand if something doesn't seem quite right

Please accept my apologies if you're already very familiar with gemology...it just said in your post that you're new to this :)

Have fun!


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 Post subject: Re: Equipment for beginners - Rough gems screening
PostPosted: Sat May 24, 2014 10:28 am 
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Joined: Sun Oct 16, 2005 12:22 pm
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Location: San Francisco
Sparkleross is spot on.
And a quote from Lisa Elser comes to mind. "If you want to make a small fortune with gemstones, start with a large fortune."


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 Post subject: Re: Equipment for beginners - Rough gems screening
PostPosted: Sat May 24, 2014 7:24 pm 
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Thank you for your prompt replies!

I should have linked my intro thread so that you have more data about context that brought me here. Sorry for that.

"I decided to register here as I start thinking about a career switch to move into gemology field.
Main reason is that
I plan to start GIA online education programme within next 12 months.
I was lucky to act a few times as a rough gem broker over last 2 years but had to use a gemologist as I have no knowledge at all, which is frustrating. I now have opportunity to buy rough stones and would like to have some independance and know how so as to supervise not only rough gems screening but also polishing and selling.
I still need to slowly phase out of my current business which should take 1 year or so. In the meantime I intend to buy some equipement and start learning on my own ; gemologyonline forum is part of that curve.
"
That being added, I need to underline that I used to know solid state physics and cristallograpy, optics, spectroscopy from fundamental physics education ; this was 15 years ago and I am not sure I can clearly link all these concepts with real life cases where I have to screen stones. At least not yet.

Let's take an example: I have 500ct+ rough diamonds to screen in 24 hours, no gemologist available. That is in the exact situation I will be soon.
I suppose I have not enough time to use microscope, and gravity kit. Refractometer will not sort out fake stones from real ones and is more relevant for polished.
These gems are rough so tricks such as steam or light deviation would not work I suppose?
I guess polariscope would help but its usage requires some sound knowledge from what I have read which I deeply lack, still.
Thermal and electrical conductivity? Would it be enough?
I can still use Raman testing but isnt it a tank to kill a fly ?
That is for diamonds, I suppose emeralds and colored sapphires testing should be slightly different?

As you probably understood, my main worry is about fake or treated stones, valuation wise I can only judge ct size and color for the moment!


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 Post subject: Re: Equipment for beginners - Rough gems screening
PostPosted: Sun May 25, 2014 2:35 pm 
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Joined: Mon May 14, 2007 11:00 am
Posts: 1133
Location: Monterey, CA
Twixt wrote:
Let's take an example: I have 500ct+ rough diamonds to screen in 24 hours, no gemologist available. That is in the exact situation I will be soon.

Diamonds - That's easy. Just look at them. Diamond has an andamantine luster. No other stone looks like a diamond, or look at them emersed in water with an incandescent light and note the dispersion.
Quote:
I suppose emeralds and colored sapphires testing should be slightly different?
As you probably understood, my main worry is about fake or treated stones, valuation wise I can only judge ct size and color for the moment!

Other emeralds and other stones - Get a complete set of Hanneman Filter Set Model 2012.
Learn to be an appraiser.
None of the above will be taught in your GIA courses.


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 Post subject: Re: Equipment for beginners - Rough gems screening
PostPosted: Sun May 25, 2014 4:56 pm 
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Joined: Sun Oct 16, 2005 12:22 pm
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Screen for what?
Color?
Clarity?
Cutting Potential?

Why would any firm give someone with NO training 500+carats of rough diamonds to screen on their own?
That doesn't make any sense.

You are currently using a Raman? What sort of a Raman and for what purpose?

A simple thermal diamond tester would be reliable with rough, just to sort real from imitation.....but this entire scenario still makes no sense.
Sorry :|


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