What is a Star Sapphire?

A star sapphire is a rare variety of sapphire which exhibits asterism (or “star stone”) under specific lighting conditions. These extraordinary sapphires contain unusual inclusions of rutile (internal minerals – titanium dioxide). These “rutile” needles intersect each other at varying angles and produce the rare phenomenon known as asterism. Under a direct light source, a six-rayed star will appear on the surface while tilting and rotating the stone. Occasionally there are two sets of these inclusions which result in 12 rays. The stones are cut en cabochon (shaped and polished, as opposed to faceted), typically with the centre of the star near the top of the dome. Star sapphires can range in colour from various tones of blue, to pink, orange, yellow, green, lavender, grey or black. The most desirable colour is a vivid, intense blue. The majority of star sapphires exhibit a white star, but star sapphire from Thailand is famed for its gold asterism.

Sapphire is a member of the corundum family and is closely related to ruby; the red to pink-red gem-quality variety of corundum, a word derived from the Sanskrit word kuruvindam, meaning ruby sapphire. All corundum has a hardness rating of 9, making it the second-hardest natural precious coloured gem, diamond being the hardest. The name ‘sapphire’ is derived from the Persian word safir, which originates from the Greek word for blue.

Many regard the Kashmir blue as the most beautiful and most valuable. These magnificent gemstones were found in 1880 after a landslide in Kashmir at an altitude of nearly 5 000 metres.

Hollywood stars and their star sapphires

 

Mary Pickford

Mary Pickford (Everett 1918)

Mary Pickford, the silent screen siren, was crazy about star sapphires. It is believed that she owned both the Star of Bombay _and_ the Star of India. She bequeathed the beautiful blue-violet Star of Bombay to the Smithsonian Institution in Washington, DC.

Jean Harlow

Jean Harlow

Jean Harlow was also known to collect large sapphires. William Powell gave her a 150-carat cabochon sapphire as an engagement ring.

Joan Crawford

Joan Crawford

Joan Crawford loved sapphires so much they were called ‘Joan Blue’. She received a 70-carat star sapphire engagement ring from her second husband, Franchot Tone, which she wore with a second 72-carat emerald-cut sapphire. ‘Mommie Dearest’ apparently also owned a bracelet set with three star sapphires of 73.15, 63.61, and 57.65 carats.

Elizabeth Taylor

Elizabeth Taylor (Bud Fracker)

Elizabeth Taylor, an avid collector of one-of-a-kind gems, was given a cabochon sapphire engagement ring by one of her husbands, Michael Wilding.

Other Famous Star Sapphires

Other famous sapphires include the Midnight Star, a 116-carat deep purple-violet sapphire of Sri Lankan origin which now belongs to the American Museum of Natural History, New York; and the Black Star of Queensland, a 733-carat black sapphire, discovered in Australia in the 1930s. The gem has been involved in several ownership disputes and now belongs to an unknown private person.