All gem-quality corundum (Aluminium oxide) that is not red in color is called sapphire. Red corundum is ruby. At 9 on the Mohs Scale of hardness, the gemstones in yellow sapphire jewelry are the third hardest natural mineral, after diamond and moissanite.
Sapphires come in many colors, and not just the blue variety for which the stones are named. In fact, orange-pink colored Padparadscha stones, a rare variety of corundum found only in Sri Lanka, are more valuable than the finest blue sapphires. The “fancy” sapphire varieties range from colorless (like diamonds) to orange, green, pink, purple and yellow – like those in yellow sapphire jewelry.
Sapphires have a prominent place in legend and history. Tradition holds that the tablets on which the Ten Commandments were written were made of sapphire, strong enough to resist a hammer blow. The ancient Persians believed that the earth rested on a giant blue sapphire and its reflection colored the sky. It’s said that the sky can sometimes be a bright canary yellow – perhaps reflecting a giant yellow sapphire, such as that used in LenYa’s yellow sapphire jewelry!