What is the name of the gemstone shown in the picture?

A star sapphire is a type of sapphire that exhibits a star-like phenomenon known as asterism; red stones are known as star rubies. Star sapphires contain intersecting needle-like inclusions following the underlying crystal structure that causes the appearance of a six-rayed star-shaped pattern when viewed with a single overhead light source. The inclusion is often the mineral rutile, a mineral composed primarily of titanium dioxide.

At 1404.49 carats, 'The Star of Adam' is the largest known blue star sapphire. The gem was mined in the city of Ratnapura, southern Sri Lanka. The value of a star sapphire depends not only on the weight of the stone, but also the body color, visibility, and intensity of the asterism. The color of the stone has more impact on the value than the visibility of the star. Since more transparent stones tend to have better colors, the most expensive star stones are semi-transparent "glass body" stones with vivid colors.

On 28 July 2021, the world's largest cluster of star sapphires, weighing 510 kg (1124.36 pounds), was unearthed from Ratnapura, Sri Lanka. This star sapphire cluster was named "Serendipity Sapphire".