Star sapphires are a unique variety of sapphire that exhibit a star-like phenomenon known as asterism. This effect occurs when light reflects off needle-like inclusions of the mineral rutile within the stone, creating a star shape that moves as the gem is rotated. Typically, star sapphires are cut into cabochon shapes to enhance this visual effect. These gemstones are primarily found in regions like Sri Lanka, Thailand, and Australia. They come in various colors, with blue being the most common. Star sapphires are valued not only for their beauty but also for their rarity, especially those displaying a well-defined star.