ASET advice/hand held ASET experts?

[lin_ny]

Just have a few questions and one on behalf of another PSer.

She kindly took this picture of the diamond I'm buying from her with her new ASET machine - but she's not sure she's using it right. She said she'd check into this thread later once she has time and post some more pictures. She said sometimes it looks all pale and grey and other times shows a lot of red, much like the picture below. Does it look like she did okay?

If she was using it correctly, how do you think the diamond itself looks?

Thanks!

 

[GemFever]

Thanks lin_ny for starting this thread! I was afraid I wouldn't have any time tonight because my parents are visiting from out of town, but I want to make sure I can get good ASETs of the OEC I'm selling, and also that I know how to use the ASET before I head to Intergem on Friday.

I need to do some reading on how to use it, but with my folks here I don't have too much time to research, and would appreciate any quick tips. How do I hold the stone properly? Can I look at set stones (like my OMCs, which have an open back, so technically light can enter, or maybe some set pieces at Intergem). Why does the ASET show such weirdly different results on the unset OEC (I'll post some pics). For people who have these, do you have any favorite light sources you use, or is the lighted base that comes with the scope the best way to view stones? Is there a really wrong way to do it?

Some pics... please comment on the stone, too!

 

[chrono]

Lin,
I'm not sure what to make of the ASET because the last few are so different from the first few. The first few has lots of red whilst the last few show a lot of green. Lots of red is good. Lots of green isn't good.

 

[diamonds-are-friends]

the aset looks decent. but the off-round/poor symmetry and very visible chip bothers me.

 

[GemFever]

Lin,
I'm not sure what to make of the ASET because the last few are so different from the first few. The first few has lots of red whilst the last few show a lot of green. Lots of red is good. Lots of green isn't good.

That's the problem I'm having -- I don't know what to make of this ASET-scope. On the Ideal Light, the OEC looks kind of watery, no sharp colors of any kind. So does the CZ that's included in the kit. AND, when you take a photo, it looks different than what the eye sees. Then, you have to bring the stone really close to the scope for it to be in focus, but I'm afraid of bringing it too close because you're not supposed to get it inside the scope. And what's up with all this variation? I just don't know what's going on. It's making me doubt my eyes -- because I see a beautiful stone, and then the ASET is all watery. Waaah! I wish I still had my 1ct OEC with the ASET from GOG, so I could compare that to what I see under the hand-held scope.

 

[bunnycat]

In the one that's showing more green, it seems the stone may be tilted a little. It seriously doesn't take much. I haven't ever used an ASET scope but I use my little Idealscope a lot. Even with the little lighted dock (for lack of a better term) to set the stone in while I look at it, it's really easy to shift or tilt the stone and get weirdness. And that is with having both hands free to take a pic! I don't know how you managed to hold the stone, the scope AND take a pic! If the final pic is one sitting in the little divet in the lighted dock, then my best guess is that is probably the one that is most close to a good reading.

 

[yssie]

Gem - the stone needs to be directly in front of of the light (you can see in the third pic you posted that the light is at an angle to the stone & scope) and the bottom of the scope needs to be on the same plane as the girdle of the stone - so only the crown protrudes into the scope itself. The last pic looks like the best, like bastet said, but even then I would guess the divot is a bit small for the stone and the girdle is a bit above the plane of the plastic that the scope is resting on, so everything's slightly skewed to a higher angle (borderline green/white looks green, borderline red/green looks red). If that's the case you could raise it a tiny bit with a few sheets of paper or cardboard - just be sure that none of it protrudes into the scope opening and blocks light to the scope


Honestly though, I sorta think an ASET for a true antique is a bit of a nonsensical proposition - they weren't designed to maximize the type of light return that tools like this reward so it's no surprise when they fail to do so! If one's definition of "most beautiful" is "performs like a modern precision-cut AVR that is designed to shine in modern overhead lighting" then antiques really aren't good candidates. An IS pic that shows a blunt ReturnsLight/Leaks/Obstructs is about as fine-grained as I'd be willing to judge by. Your pics show the basics - clean and precise faceting, no "mush", decent optical symmetry, and if I was considering buying it I'd ask for some plain closeups from face-up, a ~10deg tilt, and the side profile.

 

[bunnycat]

Gem - the stone needs to be directly in front of of the light (you can see in the third pic you posted that the light is at an angle to the stone & scope) and the bottom of the scope needs to be on the same plane as the girdle of the stone - so only the crown protrudes into the scope itself. The last pic looks like the best, like bastet said, but even then I would guess the divot is a bit small for the stone and the girdle is a bit above the plane of the plastic that the scope is resting on, so everything's slightly skewed to a higher angle (borderline green/white looks green, borderline red/green looks red). If that's the case you could raise it a tiny bit with a few sheets of paper or cardboard - just be sure that none of it protrudes into the scope opening and blocks light to the scope


Honestly though, I sorta think an ASET for a true antique is a bit of a nonsensical proposition - they weren't designed to maximize the type of light return that tools like this reward so it's no surprise when they fail to do so! If one's definition of "most beautiful" is "performs like a modern precision-cut AVR that is designed to shine in modern overhead lighting" then antiques really aren't good candidates. An IS pic that shows a blunt ReturnsLight/Leaks/Obstructs is about as fine-grained as I'd be willing to judge by. Your pics show the basics - clean and precise faceting, no "mush", decent optical symmetry, and if I was considering buying it I'd ask for some plain closeups from face-up, a ~10deg tilt, and the side profile.

+100

 

[GemFever]

Thank you bastecat and Yssie! The thing makes a lot more sense now -- the precise positioning, and the fact that it's not *really* designed for old cuts. I've just read a couple times that old cuts should be treated as fancies, and the ASET is the tool for fancies.

I'll try playing with the ASET a bit more, see if I can get things positioned correctly. This is mostly for myself, out of curiosity. Too bad it takes such precise positioning though, I thought I could take it to Intergem and use it to screen stones left and right. Guess not.

 

[bunnycat]

Thank you bastecat and Yssie! The thing makes a lot more sense now -- the precise positioning, and the fact that it's not *really* designed for old cuts. I've just read a couple times that old cuts should be treated as fancies, and the ASET is the tool for fancies.

I'll try playing with the ASET a bit more, see if I can get things positioned correctly. This is mostly for myself, out of curiosity. Too bad it takes such precise positioning though, I thought I could take it to Intergem and use it to screen stones left and right. Guess not.

You can take it with you and I guess it could be a help on things, especially if you are looking at fancy stuff. If you are just looking in general, or at rounds, I think you might have better luck with carrying an IS around since you are so much more used to dealing with images of that here than an ASET scope.

I have taken pics of stones that are set with my IS, and I think it can give you an estimate at least. I'll see if I can't dig up some pics of an IS of my ering compared to the first little diamond I bought about 25 years ago, since I still have it as it's very sentimental and to tiny to sell anyway.

My interpretation is when people liken old cuts to fancies, it's merely in the "can't trust the numbers" aspect but also I don't think you can judge an old cut by strictly on an ASET (or IS) either, as Yssie says. It kind of gives you some basic parameters to make sure there's no obvious leakage problems, and then you have to let your eyes tell you the rest.