Post subject: Old Mine cut diamond weight estimations
Posted: Mon Apr 09, 2018 4:10 pm
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Joined: Mon Apr 09, 2018 1:24 pm Posts: 8
Hello Gem experts! Could someone suggest the best formula for estimating the carat weight of old mine cut diamonds where the diamond is set in a closed-back setting? The diamond is somewhere between a wonkey cushion shape and a slight oval. I took diametres at 4 different points across. The girdle is not visible. Is it best to stick to (average Diametre)squared x Depth(estimated at 61.9% diametre) x SG x 0.0061?
Post subject: Re: Old Mine cut diamond weight estimations
Posted: Thu Apr 12, 2018 6:46 pm
Moderator: Lapidary Diamonds
Joined: Mon Aug 20, 2012 11:32 pm Posts: 1747 Location: Florida, United States
Barbra Voltaire wrote:
Also, a lot has to do with experience. Estimating, visually, exactly how deep (or shallow) the diamond may be and making corrections. Good luck!
Thanks, Barbra. That is exactly the reason why I insist on inspecting an old mine cut diamond before I provide a loss estimate. I want to look at the pavilion and crown angles, table diameter, chipping and dimensions. I tried the formula thing decades ago and found it was usually inaccurate.
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