Black Star of Queensland is a 733-carat (146.6 g) black sapphire, and was the world’s largest gem quality star sapphire. The stone was reportedly found by 12-year-old Roy Spencer in the mid-1930s in the Queensland gem fields near Anakie, Queensland. Roy showed the stone to his miner father, Harry, who assumed that it was merely a large black crystal. Not realising the value of the stone with its rough exterior, the family used it as a doorstop in their home for over a decade, until Harry took a closer look and discovered the gem hidden within. The gem has been involved in several ownership disputes.