"Strain" - help

[sailnz]

After weeks of research and self-study (all engineers suffer some degree of this malady) I attempted to purchase a diamond to mount in a tension set ring we had fallen in love with. After rejecting several stones we finally found one that seemed to meet our criteria (biggest bang for the buck). The appearance stood out from the rest. AGS0 1.0 ct H VS2 (H&A).
The ring manufacturer contacted me with a request to sign a waiver, to protect them from any claim should the diamond be damaged while mounting. The waiver states: “The diamond has a medium to thin girdle with a med.-high strain…”
This sends off all types of alarm bells to my Civil Engineering trained mind. The manufacturers’ gemologist rebuffed my calls; they do not deal with the public. The retailer we ordered the ring through has not been exactly forthcoming with information as a result of rejecting his diamond and purchasing our own. The company that sold me the diamond has been tremendous, offering to take the diamond back and replace it (I can’t face another endless search!). They managed to gleam from the manufacturer that the strain is in one corner. I have several concerns and been unable to find any definitive data or research on ‘strain’ in diamonds.
I’m considering pulling the plug on this tension ring as I’m not very happy with the way the manufacturer and retailer have chosen to handle this. They’re asking me to make decisions based on no information. I get the impression that I’m expected to just “sign the waiver as everyone else does” and not be concerned about risking what is a considerable personal investment for me. Should it be? Are my concerns justified?
Where can I find empirical data, research reports, etc. on ‘strain’? I’m sure DeBeers must have done research, this must be a consideration with the grading of roughs, and industrial diamonds (potential breakage).
How real is the risk of potential damage? What do I base my decision on? What other considerations are there?
Graham

 

[Mara]

Hi Graham. Run an archive (advanced) search on 'strain' and see what you come up with here on Pscope. The topic has definitely been discussed before.




Good luck!! One thing is that when I was talking to a company about doing a titanium tension setting, they told me to send them the cert of the stone via fax beforehand to be sure that things look good. I would assume they would want to be sure I wasn't getting something like an SI2 with feathers running from the girdles, etc. They suggested VS2 or higher with nothing near the girdle.

 

[in_need_of_help]

Would it help to buy insurance on the diamond before having it set?

 

[skibum]

Hi Graham,
When I read you were considering a tension setting, alarm bells went off in my head. I fell in love with a similar mounting a few months ago. I read though that the tension ring puts enormous pressure on the diamond and when I asked my local jeweler he explained that it is a beautiful design, but the pressure seems to make diamonds more brittle. He has had to replace several chipped diamonds from these settings, something he swears he does not do with conventional mountings.
When I finally bit the bullet, my jeweler made me a hand made platinum ring that looked similat to the Kretchmer mounting I liked, but he made acup for the stone underneath, acting like a bridge. Now the stone is actually alittle loose in the mounting, but it doesn't look like it's going to fall out.
If you want my two cents, I'd suggest finding another mounting.

Cheers,
David

 

[sailnz]

Thanks for the search tip Mara, interesting.
The retailer, the seller of the diamond, and an appraiser who valued the diamond knew it was our intention to mount it in a tension ring. They all inspected the diamond and certificate (which doesn't reflect anything to suggest/indicate the strain problem) and no-one mentioned anything. I'm not sure how they would know or discover this.
We found the ring first and went to such lengths to find the 'perfect' stone because we felt the tension ring really highlighted the diamond's beauty. The tension ring appealled to us as we are both engineers and the ring represented some very fine engineering in addition to the striking beauty.
I'm not sure insurance is the answer, I rather doubt anyone would cover a loose diamond being mounted. At present my goal is to educate myself with yet another aspect/facet of the ever expanding wide world of diamonds. Does it ever finish?
g

 

[pyramid]

I am just a consumer but have read that they see the strain if present under crossed polarized filters. There are also many posts on the Diamondtalk forum about this and Rockdoc (an appraiser who used to post there) was one of the main people who spoke about strain. I will see if I can find a post and list it here for you.

 

[pyramid]

http://www.diamondtalk.com/forums/showthread.php?t=17271&highlight=strain



here is a link which refers to another link. There are many posts over there on this subject.

 

[valeria101]

It sounds like you are really lucky: one does not see such 'strain' issues every day! Surely Jonathan at GoodOldGold took some time to dig out and picture such an extreme example on his website... I could only guess how you feel about looking for another stone, but, dare I ask, why not? This ring is a project, after all, so a major flaw found at the end just demands more time. As far as I know, tension settings are not such an established type and the technique poses new demands on the typical jewelry materials (both metal and stones) which were of no concern for traditional settings. Strain seems to be one such issue. Why risk? Finding a new diamond could be much less of a hassle now that you have already done it once and replacing a shattered diamond is a whole new type of trouble. After all, if you buy the stone independently, having it set does require some trust that the process will go well. If, in this case, the setter himself has doubts I would have twice as many (his, and mine about his!) and go the safest way. This seems to be a case of small risk paired with big exposure... the result is still a big chance to take... I would say.
You don't need a second qualification as a diamond expert, just a good ring, right?

 

[Rank Amateur]

You will find nothing definitive on strain on Pricescope or DT. Don't even bother looking unless you can stand the endless bickering between professionals. Few have any relevant experience with manufacturing tension settings anyway.

You are in a spot in that Kretchmer, who seems to be acknowledged as the main man in the tension setting biz, is telling you that he is not comfortable setting your stone. I would find a stone the that manufacturer is comfortable with or I'd find another manufacturer. Do they require their clients to sign the waiver if the client bought the stone through them? That sucks if they do. Either way, I wouldn't sign the waiver. Those compression settings (fellow BSCE telling it like it is) must do some funky things to the stone and I wouldn't mess with it. It's their product and they should take the liability - especially you are paying HUGE $$$ for the Kretchmer name and supposed expertise!

Good Luck! Tell us how it goes.

R/A

 

[spicolicpa]

"....The diamond has a medium to thin girdle with a med.-high strain…”.."

I wonder if it is the strain ONLY that has created the concern, or if it is the combination of the presence of medium-high strain and having a thin girdle...

Perhaps if the stone had no strain and retained its thin girdle it would still require a waiver?

 

[Mara]

Take the cheaper F SI1, hands down. Why pay the extra for something you can't even see, plus F is a better color, and its almost the same size anyway. Perfect example of how going right under 1c can save you $$.




Good luck

 

[aljdewey]

Oh, I'd absolutely take the F stone.....that's a HUGE difference for just 4 points. (See how brutal the carat mark can be? LOL)




Looks like a stunning choice!

 

[Richard Sherwood]

With the 59.9% depth, the F/SI1 is probably going to look as big as the 60/8% depth G/VS2, with one color grade better.

I'd go for the F, as long as it is definitely eyeclean and well cut.

 

[Garry H (Cut Nut)]

I just scanned this thread - but:

1. insurance is for ALL risks (except maybe terrorism).
2. I would want a medium to slightly thick girdle inn a tension setting - because of the risk of chipping it while wearing it - not because of the setting process.