Diamond, Platinum Necklace, JB Star. Photo Heritage Auctions

The necklace features emerald-cut diamonds weighing a total of 19.13 carats, enhanced by square-shaped diamonds weighing a total of 4.04 carats, set in platinum, marked JBS for JB Star, highlighted by a removable drop pendant suspending a pear-shaped diamond measuring 16.85 x 9.30 x 5.15 mm and weighing 5.014 carats, accented by emerald-cut diamonds weighing a total of 1.11 carats, square-shaped diamonds weighing a total of 0.82 carat, and full-cut diamonds weighing a total of 0.05 carat, set in platinum. Total diamond weight is 30.164 carats. Gross weight 49.00 grams. Estimate: $75,000 - $100,000.
Necklace Length: 16 inches
Pendant Dimensions: 2-5/8 inches x 3/8 inch

AGS, GIA and EGL certificates accompany the largest diamonds:

AGS # 0008346301 dated March 6, 2007, stating 5.014 carats G color, SI2 clarity
GIA # 14741893 dated September 21, 2005, stating 1.74 carats H color, VS2 clarity
GIA # 13408773 dated June 25, 2004, stating 1.28 carats H color, VVS1 clarity
GIA # 14062403 dated December 22, 2004, stating 1.20 carats I color, VS1 clarity
GIA # 13770599 dated October 27, 2004, stating 1.06 carats I color, VS1 clarity
EGL # NA HI29842621 dated October 1, 1998, stating 1.02 carats H color, VS2 clarity 

Heritage Auctions. 2013 April 29. Jewelry Signature Auction - New York - http://jewelry.ha.com