The Logan Sapphire is a large carats) faceted gem of outstanding color and clarity. It is mounted in a brooch setting, surrounded with white diamonds. The Logan Sapphire was gifted to the Smithsonian from Mrs. John Logan in
The Logan Sapphire Flawless sapphire is the second largest known one in the world, a staggering carats. The cushion-cut stone is one of the world's largest and most famous sapphires, set in a brooch surrounded by 20 round-cut diamonds weighing 16 carats.