Asterism in gemstones

Asterism is a fascinating optical phenomenon seen in certain gemstones, where a star-like pattern appears on the surface when light hits them at specific angles. This effect is produced by the presence of needle-like inclusions within the stone, typically arranged in a way that creates a six-rayed star. Stones like star sapphires and star rubies are popular examples. When cut into a cabochon shape (a smooth, rounded surface), these gemstones display their star beautifully as they move, making them particularly sought after by collectors and jewelry enthusiasts.