The Star of India, at 563 carats, is the largest and most famous star sapphire in the world. Formed some 2 billion years ago, it was discovered, allegedly more than 300 years ago, in Sri Lanka, where excellent sapphires are still to be found in deposits of sand and gravel left by ancient rivers. Industrialist and financier J. P. Morgan, a founding patron of this institution, presented the sapphire to the Museum in 1900. Today, the Star of India is one of the most renowned objects in all of the Museum's collections.

The presence of the mineral rutile in the Star of India gives the stone its milky quality. This also yields the star effect, as tiny fibers of the mineral, aligned in a three-fold pattern within the gem, reflect incoming light in the star pattern. This effect is known as asterism, and, along with color, is one of the characteristics that makes star sapphires so highly prized. Such stones are polished in the domed shape you can see here, called a cabochon, to best reveal the star, which moves with changing angles of illumination and observation.

In 1964 the Star of India was the object of an infamous burglary, carried out by Jack Murphy, known as Murph the Surf, and two other men. The gem was recovered several months later.