September birthstone: Blue Sapphire. September Birthstone Color is Deep Blue.

A deep blue cloudless sky. A clear mountain lake. The deep blue of a sapphire is one of the most beloved and intriguing colors known to man, a color men have spent thousands of years searching for in every corner of earth. In ancient times, people searched for a stone that would reflect the endless blue sapphire color of the sky. So its no wonder that when they found it in the sapphire gemstone, it was named the birthstone for September. September’s birthstone, in addition to being used to symbolically represent that month, is also one of the world’s favorite gemstones for use in every kind of jewelry, including engagement rings.

The ancient Greeks believed the sapphire to symbolize wisdom and purity, and reserved them for kings and priests. They believed the world itself was set upon a giant sapphire, whose color could be seen in the late summer sky. Other ancient cultures believed sapphires could protect the wearer from envious enemies and poisoning, and even that a poisonous snake could be killed by being placed near a sapphire. Ancient doctors even ground the birthstone of September into a powder and used it to treat rheumatism, depression and eye problems. The medieval female religious cleric Hildegard of Bingen wrote about the incredible healing powers of sapphires in her well-regarded book of medicine, in which she claimed that sapphires had special powers from God and could help improve the intellect.

The September birthstone derives its name from the Greek word “sapphirus” meaning blue, a word which itself comes from the Hebrew “sappir” which means to shine. Sapphires have a long and precious history in the ancient Jewish tradition. Ancient Hebrew texts claim that Noah’s Ark was illuminated with a giant sapphire used as a window, and the same stone was said to be placed in the Jewish High Priest’s breastplate, the original source of the notion of birthstones. Finally, the Ten Commandments themselves were said to have been engraved on giant sapphire tablets. The term sapphire originally applied to lapis lazuli, an extraordinarily rare and prized stone of the ancient world. This blue gem of lazurite came only from a mine in northern Afghanistan, and was given mystical and magical properties in ancient Egypt and medieval Europe. This gem was so rare that in the Middle Ages, European gemologists began referring to blue specimens of corundum, a recently discovered gem at the time, with the ancient name of sapphire.

Where do sapphires come from? In reality, a gemstone-quality sapphire is simply one variety of the mineral corundum, which is also the mineral that rubies are derived from. Any gemstone-quality corundum that isn’t red is considered a sapphire, so sapphires can actually come in many colors besides blue, including pink, yellow, and even green. One extremely rare color type, the orange-pink corundum, is known as the Padparadscha sapphire. The most valued sapphire color, however, is that deep dark blue that is the well-known September birthstone color. Sapphires are mined all over the world, from Australia, Sri Lanka, Kenya, China, and the United States. The most famous sapphire, the 563-carat Star of India, was mined in India and is now on display at the American Museum of Natural History in New York. However, this famous stone is not the world’s largest—that honor belongs to the “Lone Star” a 9,719.5 carat blue sapphire that has been validated by the gemologist community but has never been displayed to the public.

Of all the birthstones, September is one of the most suited for use in jewelry. Sapphire has a high degree of mineral hardness bested only by diamond, making it durable and secure enough for use in every kind of jewelry setting. It was set as the official birthstone for September by the American National Association of Jewelers in 1912, and is also commonly used to commemorate the 5th, 23rd, and 45th wedding anniversaries. A more rate form of sapphire, the star sapphire, is used to mark the very rare and special occasion of a 65th wedding anniversary. The star sapphire is one with tiny inclusions shaped like needles, which give it an optical property known as asterism, or a star-like appearance. This star shape appears most prominently in a cabochon cut and can have between six and twelve rays or even a cats-eye effect with a single thin band of light down the middle of the stone.

Although sapphires are available in a wide variety of price ranges, the savvy consumer would do well to know that sapphires can be created synthetically in a lab, yielding stones that are pretty and sparkly but do not have the value of a genuine mined stone. Small stones in less-expensive birthstone jewelry, especially for children, are often lab-created—for larger and more valuable pieces, a reliable gemstone certification will help ensure that your stone is the real deal. Many treatments can be performed on a sapphire to improve its color and clarity—this kind of information should all be clearly revealed on a gemstone certification.

Sapphires have been popular since ancient times, but they have never been as hot as they were this year. When Prince William of England, son of the beloved late Princess Diana, proposed to his longtime girlfriend, Kate Middleton, with his mother’s 18-carat diamond-studded sapphire engagement ring, the world went wild for sapphire. Of course, sapphires had also shot to popularity when Princess Diana first wore the ring in the 1980’s, but Kate Middleton’s status as an international fashion icon, as evidenced by the royal-blue Issa dress she wore to highlight the gorgeous blue color of her ring, has catapulted sales of the gemstone to never-before-seen heights. No longer just the September birthstone, the sapphire is now one of the most popular and sought-after stones for necklaces, earrings, and engagement rings. As the stone represents the important but old-fashioned qualities of sincerity and faithfulness, it seems only right that it receive its rightful turn in the spotlight.