September Birthstone

Sapphires make stunning jewelry gifts for anyone born in September or celebrating a 5th or 45th wedding anniversary. Whatever your reason for buying sapphire, you can’t go wrong with this brilliant gemstone, whether you’re seeking classical blue or another shade of the sapphire rainbow.

The quality factors of sapphires are not as clearly defined as other gemstones like diamonds, but generally, the 4Cs still apply. Like diamonds, sapphires are assessed by color, clarity, cut, and carat size, in addition to country of origin. 

Color is the key indicator of a sapphire’s price. The highest valued sapphires are vivid blue, sometimes with a violet hue. Secondary hues of green or gray detract from sapphire’s value.

Sapphire gemstones come in almost any color except red, which is classified as ruby. Pinkish-orange varieties are known as padparadscha, and these typically have higher per-carat values than other colors of fancy sapphire.

Some sapphire stones even exhibit color change, shifting from blue in daylight or fluorescent light to reddish-purple under incandescent light, much like the color-changing alexandrite gemstone.

Blue sapphires typically have better clarity than rubies, though they often have long, thin rutile inclusions called “silk.” Inclusions generally make gemstones less valuable, but they can increase the value of sapphires that exhibit asterism—or stars—the four- or six-rayed star pattern of light produced by the fibrous inclusions, elongated needles, or growth tubes in a gemstone. This singular, celestial-like phenomenon is best seen in a gemstone cut en cabochon.

Blue sapphire gems can range in size from a few points to hundreds of carats. Most commercial-quality blue sapphires weigh less than five carats. Large blue sapphires, while rare, are more readily available than large rubies.

The 423-carat Logan Sapphire in the National Museum of Natural History is one of the largest faceted gem-quality blue sapphires ever found. The Star of Adam is the largest blue star sapphire, weighing 1404.49 carats.

Sapphires are often treated with heat to improve color and clarity. Untreated natural gemstones are somewhat rare and incredibly valuable.

If you are looking for sapphire birthstone jewelry, find an American Gem Society jeweler near you.