Look closely at the AGL report for his listing. Not bad for a stone from Oz, eh? Could fool a lot of folks into thinking its a Burma blue.
http://www.ebay.com/itm/Cartier-Platinum-3-15ct-Natural-Sapphire-3-25ct-Diamond-Halo-Ring-size-5-AGL-R2-/191255999726?pt=US_Fine_Rings&hash=item2c87bef4ee
http://www.ebay.com/itm/Cartier-Platinum-3-15ct-Natural-Sapphire-3-25ct-Diamond-Halo-Ring-size-5-AGL-R2-/191255999726?pt=US_Fine_Rings&hash=item2c87bef4ee