Star sapphire is a respected member of the corundum family. Red corundum is called ruby. All other color varieties of corundum being referred to as sapphire. Corundum is the second hardest substance on the Mohs scale, with a rating of nine. Diamond tops that scale with a ten. That hardness combined with the rich color and silky shine make fine sapphires extremely valuable.
Star sapphires contain unusual tiny needle-like inclusions. Those rutile needles result in a silky shine on the surface of the gem. Aligned needles that intersect each other at varying angles produce a phenomenon called asterism (Latin aster for star). Because of their crystal structure, only the star sapphire and the star ruby show six white rays of light that meet in one point and dance over the gem's surface when viewed from different directions.
Star sapphire range in color from blue in various tones, pink, orange, yellow, green, lavender, gray to black. The most desirable color is a vivid, intense blue.
Star sapphire is a durable, popular stone for men's rings. A black star sapphire supports a masculine image best. In ancient times, star sapphire was regarded as a powerful talisman guiding travelers and seekers of all kinds.