What Is the September Birthstone? Sapphire

Short answer: sapphire is the September birthstone. It is the mineral corundum in any color except red; red corundum is ruby. Sapphire is best known in velvety blue but also comes in pink, yellow, orange, purple, green and colorless. It rates 9 on the Mohs scale, second only to diamond among popular gems, which makes it ideal for everyday rings.

What is sapphire?

Sapphire is corundum, crystalline aluminum oxide. Pure corundum is colorless; traces of other elements give it color. Blue comes mainly from iron and titanium substituting together in the crystal. Red corundum is called ruby, and every other color is sapphire.

At 9 on the Mohs scale, with excellent toughness and no cleavage, sapphire is one of the most durable gems, well suited to rings and jewelry worn every day.

What colors does sapphire come in?

• Blue is the classic September color, from pale to deep, velvety blue.
• Fancy sapphires come in pink, yellow, orange, purple, green and colorless.
• Padparadscha is a rare sapphire in a narrow range of pinkish orange to orangey pink.
• Star sapphire shows a star of light, called asterism, when cut as a cabochon, caused by microscopic inclusions.
• Color-change sapphire looks a noticeably different color under different light sources.

Where does sapphire come from?

Kashmir, Myanmar and Sri Lanka are the three historically important sources.

• Kashmir: sapphires were found around 1881, when a landslide high in the Himalayas exposed a pocket of velvety "cornflower" blue crystals. Thousands of large crystals were recovered between 1882 and 1887, establishing Kashmir sapphire as one of the most coveted gems in the world. Production since has been sporadic.
• Myanmar: the Mogok area produces sapphire alongside ruby. "Burmese" sapphire is prized for its rich, intense blue.
• Sri Lanka: a source for more than 2,000 years, from alluvial gravels. Milky white "geuda" sapphires from Sri Lanka can be heat treated to a rich blue.

Sapphire also comes from Australia, Thailand, Cambodia, Madagascar and the United States, especially Montana. Thailand is a major cutting and treatment center, at Chanthaburi and Bangkok.

Famous sapphires

The Rockefeller Sapphire, a 62.02 carat step-cut stone from Myanmar, was bought by John D. Rockefeller Jr. in 1934 from an Indian maharaja. The Star of India, a 563.35 carat star sapphire from the J. P. Morgan collection, is held by the American Museum of Natural History in New York, and was among the gems taken in a widely reported museum jewel theft in 1964. Perhaps the best-known sapphire today is the 12 carat blue stone surrounded by diamonds in the engagement ring first worn by Princess Diana and later given to Catherine, now Princess of Wales.

What is sapphire traditionally associated with?

Sapphire has traditionally symbolized sincerity, truth, faithfulness and nobility, and it has adorned royalty and the robes of the clergy for centuries. The elite of ancient Greece and Rome believed blue sapphire protected its owner from harm and envy. Medieval clerics wore it because it symbolized Heaven, and ancient Persians held that the earth rested on a giant sapphire that colored the sky blue. Sapphire is the gem of the fifth and forty-fifth wedding anniversaries.

These are traditions and beliefs, not properties of the stone.

Is sapphire treated?

Often. Heat treatment is common and permanent, and it is well accepted in the trade. Less common treatments include lattice diffusion, fracture filling and dyeing. Diffusion can create color so shallow that recutting a chipped stone could remove it, and fracture-filled or dyed sapphires can be damaged by mild acids such as lemon juice. Always ask whether a sapphire is treated, and how.

Synthetic sapphire, grown in laboratories, has the same chemistry and hardness as natural sapphire. It is used in jewelry and in industry, and it should be sold as synthetic.

How do you care for sapphire?

• Clean it with warm, soapy water and a soft brush, which is always safe.
• Ultrasonic and steam cleaners are usually safe for untreated and heat-treated stones, but not for fracture-filled, dyed or diffusion-treated ones.
• Store it apart from softer gems, which sapphire can scratch.

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Frequently asked questions

What is the September birthstone color?

Blue is the traditional September color, but sapphire also comes in pink, yellow, orange, purple, green and colorless.

Is ruby a sapphire?

Ruby and sapphire are the same mineral, corundum. Red corundum is called ruby; every other color is sapphire.

Why are Kashmir sapphires so valuable?

The Kashmir deposit, found around 1881, produced a short burst of exceptional velvety cornflower-blue crystals between 1882 and 1887, and production has been sporadic since. That rare color and limited supply make them some of the most coveted gems in the world.

Are most sapphires heat treated?

Heat treatment is very common, permanent and accepted in the trade. Other treatments, such as diffusion, fracture filling and dyeing, are less common and need special care. A seller should always say how a sapphire has been treated.

Is sapphire durable enough for an engagement ring?

Yes. At 9 on the Mohs scale, with excellent toughness and no cleavage, sapphire is one of the most durable gems for everyday rings.

Sources

• GIA, September Birthstone: https://www.gia.edu/birthstones/september-birthstones
• GIA, Sapphire: https://www.gia.edu/sapphire
• Wikipedia, Sapphire: https://en.wikipedia.org/wiki/Sapphire
• Wikipedia, Corundum: https://en.wikipedia.org/wiki/Corundum