Star sapphires and rubies are gems that display asterism. All star rubies and star sapphires will be cut into rounded forms. The curved surface is what allows for the star to be created.The pattern is caused by light bouncing off mineral rutile inclusions within the gemstone. Because the star needs rutile needles to appear, the best clarity possible in star corundum is semi-transparent.Star sapphire is often called the ‘gem of heaven’ and is associated with hope, potential, and dreams. Star rubies are amongst the rarest and most coveted gems in the world