STAR SAPPHIRE (ASTERISM)
September brings us to one of the popular gems in the world the Sapphire! Sapphires come in deep blue, Ceylon blue, blues with slight lilac hues as well as pink and yellow sapphires. But let's focus on the Star Sapphire today.
When we talk of Asterism, we talk about rubies and sapphires. Rutile inclusions ( also known as silk), when interacting with light, create the likeness of a star and so is born the star sapphire or star ruby. When needle-like inclusions (often minerals composed of titanium dioxide) intersect following the underlying structure of the crystal, it creates a six-rayed pattern, exhibiting this star-like phenomenon which is called Asterism. These crystals are cut in cabochon as seen in picture, with the star on the top of the dome. On rare occasions we can find stars in gems with more than six beams and, sometimes with even twelve beams.Legends have been told and poems written saying the first star rubies and sapphires were created by a sunbeam, in love with a gorgeous star.
The Black Star of Queensland is believed to be the largest star sapphire ever mined weighing 733 carats, discovered in the 1930s in the Anakie Sapphire fields of the Rubyvale area in the State of Queensland, in northeastern Australia. Followed by the Star of India weighing 563.4 carats. The latter is currently in display at the American Museum of Natural History, in NY city.
The visibility and intensity of the Asterism (the star-like pattern) along with the weight will determine the value of the Star Sapphire. The Black Star of Queensland would make its way around the world, weaving in and out of spotlight and obscurity, with stops in the Smithsonian in the '60s, on Cher's neck in the '70s, and at the Royal Ontario Museum in Toronto in 2007. Currently, the sapphire is owned by an unknown private party and is not believed to be on public display.