well not set as rings (the largest there was i beleive around 60ct pear shape) but neckpieces yes. where well at some jewellers i know in london paris and geneva andi tell you once the pure rock is transformed into a jewellers vision it can look extremely wonderful
since you are in the states and if you want to take a look at larger stones if you get the chance to visit leviev in NYC do so he has normally some 30+ ct stones lying around (though i must admit his london location is much better stocked)
regading the auction: i do not believe the stone beeing d or if as the price (6mil) actually seems quite modest so it either is a very low estimate or there issomething more to the stone (or the shape could play a role in that)
i acctually dont mind the cut, its not something i would choose but its not bad, its unusual. I guess it appeals more to me cos im a guy and the harsh lines are more masculine.I could see it as a pendant, maybe a broach but not much else.