September Birthstone: Sapphire — Color, Meaning & Jewelry Guide

By Tolga Kavut, founder of Glamour Jewelry House · Updated September 2026

The September birthstone is sapphire — the blue of royal engagement rings, medieval cathedral windows and every promise anyone ever meant. For three thousand years sapphire has stood for truth, faithfulness and clear judgment, which is why it ended up on the fingers of kings, clergy and, more recently, a British princess whose ring the whole world recognizes.

Sapphire is also the practical choice hiding inside a romantic one: at 9 on the Mohs scale it is the second-hardest gem there is. Here is the September birthstone in full — including the fact that sapphires come in nearly every color, which surprises most people who own one.

Shop September birthstone jewelrySee all 12 birthstones

September birthstone at a glance

What color is the September birthstone?

Blue is the answer everyone expects, and the ideal is a velvety, medium-deep royal blue — the shade historically associated with Kashmir, still the most coveted color in the trade. Too dark and the stone goes inky; too pale and it loses presence.

But here is the part that delights September babies: sapphire comes in every color except red. Pink, yellow, green, violet, black, colorless, and the rare and lovely peachy-pink padparadscha named after the lotus flower — all are true sapphires, because sapphire is simply corundum that isn’t red. (Red corundum is ruby.) If blue isn’t your color, you can wear a genuine September birthstone in almost any shade you like.

What does the September birthstone mean?

Truth, and the keeping of promises. Ancient Persians believed the earth rested on a giant sapphire whose reflection colored the sky. Medieval clergy wore sapphire rings as a symbol of heaven and of vows kept; it was thought to protect the wearer from envy and to reveal deception. That reputation is exactly why sapphire, not diamond, was the traditional European engagement stone for centuries — and why it keeps returning to royal engagement rings today.

A short history of sapphire

Rome carved it, the medieval church revered it, and in 1881 a landslide in the Kashmir Himalayas exposed a deposit whose velvety cornflower-blue stones became the standard against which every sapphire since has been measured — the mine was essentially exhausted within a few decades, which is why Kashmir sapphires now sell for extraordinary sums. Ceylon (Sri Lanka) has produced fine sapphires continuously for over two thousand years, and Montana’s deposits have made American-mined sapphire a real option for buyers who care about origin.

How to buy a good sapphire

Judge color in daylight. Sapphire changes character under different lighting more than most gems. A stone that looks superb under a jeweler’s spotlights can go flat and inky outdoors — always ask to see it by a window.

Heat is standard; disclosure is mandatory. Most sapphires on the market are heat-treated to improve color and clarity, permanently and stably. Unheated stones with fine color carry a significant premium and should come with a lab report. Diffusion-treated and lead-glass-filled stones are a different, lesser category — ask directly.

Consider the non-blues. Yellow, green and teal Montana sapphires cost a fraction of fine blue and are just as durable — the best value in September’s birthstone by a wide margin.

Caring for sapphire jewelry

Effortless. At 9 Mohs, sapphire handles anything daily life offers; warm soapy water is all it needs. Only glass-filled stones require gentler care — another reason to ask what you are buying.

Shop September birthstone jewelry

Every piece is made to order in 18K gold — choose sapphire at checkout for a September birthday, and add a name, initial or date if you’d like it engraved.

Natural Birthstone NecklaceFrom $57 Birthstone RingFrom $57 Teardrop Birthstone NecklaceFrom $58 Family Birthstone NecklaceFrom $59 Personalized Birthstone BraceletFrom $59 Custom Name Necklace with BirthstoneFrom $59

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September birthstone jewelry: where to start

Sapphire is the birthstone I recommend most freely for rings. Its hardness means a September birthstone ring can be worn every single day for decades, which is precisely why it became an engagement stone in the first place.

For everyday elegance, a bezel-set September birthstone necklace puts that blue exactly where it catches the eye, and engraving a name or date turns it into a keepsake. In a family birthstone necklace or personalized birthstone bracelet, a September stone gives the lineup its deepest, most anchoring color.

September birthstone questions

What is September’s birthstone?

Sapphire — blue corundum, the stone of truth and faithfulness, and September’s only official birthstone.

What color is the September birthstone?

Classically royal or cornflower blue, but sapphires occur in every color except red, including pink, yellow, green, violet and the rare padparadscha orange-pink.

Are sapphire and ruby the same stone?

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

Is sapphire good for an everyday ring?

Yes — at 9 on the Mohs scale it is second only to diamond in hardness, which is why it has been an engagement stone for centuries.

Are sapphires treated?

Most are heat-treated, a permanent and accepted practice. Unheated stones carry a premium; diffusion and glass-filled treatments are lesser and should always be disclosed.

Birthstones for every month

Each month has its own guide to its stone, color and meaning — or start with the complete birthstones by month chart.

• January birthstoneGarnet · Deep red
• February birthstoneAmethyst · Violet purple
• March birthstoneAquamarine · Sea blue
• April birthstoneDiamond · Colorless
• May birthstoneEmerald · Vivid green
• June birthstonePearl · Cream white
• July birthstoneRuby · Rich red
• August birthstonePeridot · Olive green
• September birthstoneSapphire · Royal blue
• October birthstoneOpal · Play-of-color
• November birthstoneTopaz · Golden yellow
• December birthstoneTurquoise · Robin’s-egg blue

You might also like

• July birthstone — ruby, sapphire’s red corundum twin
• March birthstone — aquamarine, the softer blue birthstone
• December birthstone — turquoise, tanzanite and blue zircon