RAPAPORT... A 21.13-carat diamond ring will lead Leonard Joel’s upcoming Important Jewels auction, where it is expected to fetch up to AUD 900,000 ($620,362).The cut-cornered square modified brilliant-cut, K-color, SI2-clarity diamond ring is one of a number of large stones that will feature in the August 16 sale in Sydney, Australia. The auction could garner as much as AUD 8.6 million ($5.9 milli...
