Diamond A rare blue diamond, The Heart of Eternity, is a famous precious stone currently owned by the De Beers Group. Now at 27.64 carats, this heart-shaped wonder was originally crafted from a 777 carat stone. Another famous blue diamond is The Hope Diamond, previous owned by Evalyn Walsh McLean and known for causing her bad luck. Ruby A well known ruby is the Liberty Bell Ruby, originally discovered in east Africa in the 1950’s. At 8,500 carats, it was valued at two million dollars. This stone had been sculpted into the shape of the Liberty Bell, but was stolen from a jewelry store in Delaware in November of 2011. It is the largest known ruby in the world. Emerald The Patricia Emerald, at 632 carats, is the largest uncut emerald in existence. Named after the mine owner’s daughter, this gemstone was discovered in Colombia in 1920 and can be seen on display at the American Museum of Natural History in New York. Sapphire The largest known sapphire, titled the Black Star of Queensland, is black in color and was discovered in Australia in the 1930’s. At 733 carats, it was once on display at the Smithsonian and then at the Royal Ontario Museum. It has since been purchased by an unknown buyer, and is no longer displayed.