Chips under prongs

[unc1]

I am curious about the frequency with which diamonds crack or chip during setting and routine tightening. Is it "common" for a diamond to be damaged during these processes? Is it more common during initial setting than when prongs are tighened after wear?

Finally, how would you know if your diamond were damaged beneath the prong without having the stone removed and examined? Would anything be visible to the naked eye?

Thanks for your expert insights!

 

[valeria101]

Someone who sets diamonds for a living (not I) will be in a better position to devise stats... There were similar questions some time ago, and the answers read "not common at all". The type of cut makes a difference: for example, the tips of a princess cut seem to be somewhat prone to getting damaged. Round cuts do not have such "structural" issues.

A chip may not be visible under the offending prong: usually this is a tiny thing. If you really get unlucky (or the diamond has some issue that makes it prone to chipping) and the stones get seriously damaged, than. well, it will show. However, if the stone is sound and the jeweler professional, you really need a serious doze of bad luck to get your RBC stone visibly damaged (or damaged at all). These are possible events, but very improbable ones.

 

[niceice]

It takes a bit of work to chip a diamond during the setting process unless the girdle edge is less than 0.7% thin, in other words unless the girdle edge is Extremely Thin to Very Thin... But when it does occur, the chip is usually substantial enough that it is easy to see around the prong. We have a jeweler around the corner from us that has purchased more than a few diamonds from us at the last minute because his wife has lost control of the ring while polishing it and the diamond gets chipped as the ring slams against the metal edge of the polishing unit as it flies off of the wheel... For those of you who aren't familiar with a polishing unit, it is like a large bench grinder with soft wheels on it that are used for polishing... We don't know what the RPM's are off hand (we'd have to look at the unit and haven't left for the store yet this morning) but that puppy is flying pretty fast... So when a ring gets spun off of the wheel it is flying... So you can imagine the impact upon the diamond when it hits the edge of the polishing unit... As we recall, she's managed to chip four diamonds in the past year, that's more diamonds than we've seen chipped by experienced bench jewelers (journeymen level) during the setting process in more than twenty years! So while the jeweler might be an expert setter, his wife is costing him a fortune! Long story short, don't let an apprentice work on your stuff!