BLACK STAR OF QUEENLAND

Black Star of Queensland is a 733-carat (147 g) black sapphire, and the world's largest gem quality star salpphire It was discovered in Australia in the 1930s.The gem has been involved in several ownership disputes.
The Black Star of Queensland was on display during the 1960s at the Smithsonian as part of a display with the hope diamond  From 2 June through 2 December 2007, it was on display at the royal ontario musiam The sapphire is now owned by an unknown private party and is not believed to be on public display.
The star of india at 563.4 carats (112.7 g) is thought to be the second-largest star sapphire, and it is currently on display at the american musium of natural history in new york city