This ia an extremely rare collector's gem as it is a Flawless Cobalt - Vivid Blue Spinel with 5.30 Carat and dimensions 10.71 x 8.72 x 5.94 (mm) as Certified by GRS. Blue spinel is also known as cobalt spinel, gahnospinel or sapphire spinel. The prized colour is abination of well-balanced trace element in the gems crystal structure, typically cobalt and iron. This rare and exceptional vivid blue spinel, without steely grey overtones are the most sought after and examples over 5 carats are even considered extremely rare. Note: Most reputable auction house that auctioned out such gems are mostly Cobalt Blue Spinel and not Vivid Blue Spinel.