Asterism (geology)

Asterism in geology refers to a unique optical phenomenon seen in certain minerals, where a star-shaped pattern appears on the surface when light reflects off them. This effect is typically found in cabochon-cut stones, like star sapphires or star rubies. The star shape is created by tiny needle-like inclusions within the mineral that arrange in a specific way, reflecting light in a star-like formation. Asterism adds beauty and value to gemstones, making them sought after in jewelry.