Sapphire is the gemstone for those born in September. When someone says sapphire we most often think of a blue gemstone. But, did you know that sapphire, a form of the mineral corundum, comes in every color but red? Red corundum is called ruby. Sapphire is the most prized blue gemstone. Its color has been described as velvety blue, cornflower blue, sometime deep liquid blue. People of ancient Persia believed that the earth sat on a giant blue sapphire causing the sky to be blue. Sapphire measures 9 on the mohs scale, making it one of the most durable gemstones. Besides its beauty its hardness makes it an excellent gemstone for all jewelry.