Star sapphire is a fascinating gemstone known for its unique asterism, which is a star-like phenomenon that appears on the surface when light reflects off the stone. This effect is caused by the presence of needle-like inclusions of rutile within the sapphire. Star sapphires typically come in a deep blue color, but they can also be found in shades of pink, yellow, and green.

The star effect is most prominent when the stone is cut into a cabochon shape, allowing the light to reflect in a way that creates a star with six rays. This gemstone is highly valued not only for its beauty but also for its metaphysical properties, which are believed to include protection, good fortune, and the ability to enhance intuition.

In terms of hardness, star sapphires are quite durable, ranking 9 on the Mohs scale, making them suitable for various types of jewelry. Their brilliance, combined with the captivating star effect, makes star sapphires a popular choice among gemstone enthusiasts.