Asterism

Asterism is a phenomenon observed in certain gemstones where a star-like pattern appears on the surface when viewed under light. This effect is caused by the arrangement of needle-like inclusions within the stone, which reflect light in multiple directions. Common gemstones that exhibit asterism include star sapphires and star rubies. The result is a beautiful, star-shaped reflection that moves as the stone is turned. Asterism enhances the gem's attractiveness and can significantly impact its value in the market.