Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Thu Nov 15, 2012 7:04 pm
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Joined: Wed Jun 15, 2011 8:29 am Posts: 123 Location: London
Don't go crazy, it's not only about the equipment, your skills and knowledge are more important, better tools just help. I know some gem dealers in third world countries that identify stones just by looking at them, and are rarely ever mistaken, they just have seen a ton of that stuff and know how it looks feels and smells
Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Mon Nov 26, 2012 12:07 am
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Joined: Thu Nov 08, 2012 8:33 am Posts: 102
Thanks, Kane. I'm limiting my purchases to the OPL spectroscope and dichroscope, a cheap Ebay hand-held polariscope, a good led pen light, a 6$ eBay 60x led-loupe, my original 10x loupe, and an SG kit from Prettyrock.com. I'm planning on buying a cheap Ebay refractometer and going to splurge on the Presidium duo. I'm not going to purchase a microscope for a while since I'm all inclusions seem to look the same to me (doh!). I did manage to ID curved striations in a fake sapphire with my 6$ loupe, which made me extremely happy. I couldn't see the striations with a $65 hand-held dark field loupe so I decided that it was either flawed or I don't know how to use it. The optics seemed questionable since it was fuzzy around the edges, so I returned it (it was supposed to a quality triplet, but my 20 year old 10x loupe from Japan leaves it in the dust).
Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Mon Nov 26, 2012 8:38 pm
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Joined: Thu Nov 08, 2012 8:33 am Posts: 102
Thanks for the advice, Barbara. I'll consider it. I received my OPL instruments last week from Colin Winter. He is such a great guy. Using my new spectroscope, I looked at a rough Tsavorite I received from Prettyrock.com. To my eyes, it looks like the absorption is at both ends, both in the red and the blue. Could this be right? I'll try and photograph it tonight.
Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Mon Nov 26, 2012 10:49 pm
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Joined: Mon Apr 16, 2007 12:05 am Posts: 1499
Absorption in red region (600-700 nm) and blue region (400-500 nm) is why the gem looks green. In the grossular spectra shown halfway down this page, the peak light intensity occurs around 530-540 nm, which is the same green as the little ring in my icon.
Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Tue Nov 27, 2012 3:07 am
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Joined: Thu Nov 08, 2012 8:33 am Posts: 102
Here's a trillion tsavorite (the original gem that started this post).
I shot these photos by holding my camera in my right hand (too lazy to get the tripod out) and shooting about 12 inches away from my 6$ loupe. The gem is lit by my LED pen light.
Here's one of my shots close up:
These inclusion occupied a flat plane that cut diagonally down the gem. It looked kindof like a fingerprint.
Here's another close up:
These inclusions occupied an outside corner.
I tried to shoot the spectrum but it only looked like there wasn't any absorption lines. I will try again using my Ipad.
Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Tue Nov 27, 2012 3:34 am
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Joined: Thu Nov 08, 2012 8:33 am Posts: 102
Here's the tsavorite trillion spectrum taken with the Ipad.
Didn't really capture what I saw - strong absorption in the blue side mostly, depending on what method I used. When I viewed the stone in another way, there seem to have fuzzy absorption line in between the green and blue zones.
I use the Chelsea filter all the time when buying rough, and find it very useful to separate non Chrome green tourmaline from chrome when going through a parcel. You are right, you tsavorite should show red under the filter.
I think your problem is your light source. You need to use a good old fashioned incandescent light. If you are using these new CFL bulbs or even most LED your results will not be good. Hold the filter right up to your eye, and with the stone on some white tissue hold it under a strong incandescent light.
Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Tue Nov 27, 2012 6:00 pm
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Joined: Thu Nov 08, 2012 8:33 am Posts: 102
I've been rummaging around my house and we don't have tungsten flashlight. My tsavorite rough also does not glow red under chelsea filter.
I've taken a few more photos, this time using a Canon PowerShot (my Sony battery is dead) and also using my son's student micro cope. It has a really annoying black pointer in the middle of the viewfinder.
tsavorite rough @ 100x (10x eyepiece + 10x power)
Here's a close-up:
I also shot a sapphire rough:
Here's the sapphire under the microscope:
Here's the inclusion close-up:
Are these inclusions typical of tsvorites (kindof pebbly)? What is the inclusion in the sapphire?
Post subject: Re: Purchased Tsavorites that do not register red Chelsea fi
Posted: Wed Nov 28, 2012 2:25 am
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Joined: Thu Nov 08, 2012 8:33 am Posts: 102
Ok. Will take more spectra photos when I purchase tungsten flashlight. Do you have any opinion about the tsavorite inclusions? They do not look like bubbles. I can't ID the shape since I'm new at this. I think the sapphire inclusion would be difficult to ID without some kind of high end tool unless it is common to that kind of stone.
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