If you were born in September, or you’re shopping for someone who was, you’ve probably already landed on the answer: the september birthstone is sapphire. That part is easy. What’s less obvious is everything sapphire actually covers, because it’s a far bigger, stranger and more interesting stone than the single word “blue” suggests.
Sapphire has been worn by kings, buried with clergy, set into some of the most photographed engagement rings in modern history, and mined from mountain ranges in Kashmir, Myanmar and Sri Lanka that have supplied gem traders for over a thousand years. It also comes in colours that have nothing to do with blue at all. This guide walks through what the september birthstone actually is, why sapphire earned that title, how to judge whether one is worth buying, and how to look after it once it’s yours, especially if “yours” happens to live in a humid, salty, sun-drenched place like Bali.
What Is the September Birthstone?
Sapphire is the modern september birthstone, a title it’s held since jewellers’ associations in the early 20th century formalised the birthstone list most people still use today. Before that, birthstone traditions were far less standardised. Some historical lists, including an older Tibetan association, actually placed lapis lazuli in September’s slot instead, which is part of why you’ll occasionally see lapis mentioned alongside sapphire in older birthstone charts.
What makes this a little confusing at first is that sapphire isn’t a single colour of stone. It’s a variety of the mineral corundum, and corundum comes in almost every colour except one: red. Red corundum gets its own name, ruby, and everything else on the corundum spectrum, blue, pink, yellow, green, violet, and colourless, falls under the sapphire umbrella. So when someone says “sapphire,” they’re really describing a stone by what it is, not what colour it’s wearing.
A Short History of Sapphire as September’s Birthstone
Sapphire’s reputation didn’t start with a marketing committee. Ancient Persian belief held that the sky itself was blue because it reflected off a giant sapphire the earth rested on, which is a fairly good origin story for a stone. Medieval European clergy wore sapphire rings as a symbol of heaven and purity, and by the Middle Ages it had become closely associated with royalty and protection, worn by rulers who believed it guarded against envy and harm.
That royal association never really faded. It’s part of why sapphire has appeared in some of the most recognisable engagement rings of the last century, most famously the blue sapphire surrounded by diamonds that Princess Diana wore, and which Catherine, Princess of Wales, wears today. Whether or not that history matters to you personally, it says something about the stone: sapphire has always been treated as a gem for meaningful, lasting commitments, not just decoration.
What Does a Sapphire Actually Mean?
Strip away the royal history and sapphire’s traditional meaning comes down to a fairly consistent set of ideas across cultures: wisdom, loyalty, and protection. Ancient scholars believed sapphire sharpened the mind and encouraged honesty in the person wearing it. It’s also long been tied to fidelity and trust, which is a large part of why it works so well as a gift between people who are committing to each other, whether that’s an engagement, an anniversary, or simply a milestone worth marking.
In astrology, sapphire is often linked to Virgo (the zodiac sign that shares September) as a stone believed to bring calm and clarity, though it’s also associated with Sagittarius in some traditions. None of this is something you need to believe to appreciate the stone, but it’s part of why sapphire has stayed relevant as a meaningful gift rather than fading into just another gemstone option.
Sapphire Comes in More Than Blue
This is the part most people miss, and it’s genuinely worth knowing before you shop. Blue sapphire is the most recognised version of the stone, prized for centuries and still the default choice for engagement rings and classic jewellery. But “fancy sapphire,” the trade term for any non-blue sapphire, opens up a much wider and often more distinctive set of options.
Padparadscha, Pink, Yellow and Green Sapphires
Padparadscha is the rarest and most sought-after of the fancy sapphires, a delicate blend of pink and orange named after the colour of a lotus flower, and genuinely rare enough that fine examples command serious attention from collectors. Pink sapphire has become a popular alternative to pink diamond for exactly that reason: similar look, considerably more attainable. Yellow sapphire brings warmth without the cost of a fancy yellow diamond, and green sapphire, though less commonly seen, offers something genuinely unusual for anyone who wants a coloured stone that isn’t blue, pink, or the expected default.
Star Sapphires: When Light Moves Inside the Stone
Some sapphires contain tiny needle-like inclusions of a mineral called rutile, arranged in a way that reflects light as a six-rayed star across the surface of the stone when it’s cut into a smooth dome (called a cabochon) rather than faceted. This effect, called asterism, turns what would otherwise be considered a flaw into the entire point of the stone. A good star sapphire is a genuinely different buying experience from a faceted blue sapphire, prized for the phenomenon itself rather than clarity or brilliance.
Is Sapphire a Good Stone for an Engagement Ring?
Yes, and the reason comes down to something more practical than meaning or history: hardness. Sapphire sits at 9 on the Mohs scale, the standard measure of a mineral’s resistance to scratching, which makes it the second-hardest natural gemstone after diamond. That’s a meaningful difference from softer coloured stones like opal or emerald, which need far more careful handling to avoid damage over years of daily wear.
In practice, that means a sapphire engagement ring can genuinely hold up to the same daily knocks as a diamond one, cooking, gardening, workouts, and all, without the anxiety that comes with a more delicate stone. Combine that durability with the colour range covered above, and it’s easy to see why sapphire has become one of the most common diamond alternatives for engagement rings, not as a compromise, but as a deliberate choice for people who want a coloured stone with the meaning to match.
What Actually Affects a Sapphire’s Value
Coloured stones don’t follow the exact same grading system as diamonds, but the underlying idea, judging a stone across a few key factors, still applies. Here’s what actually moves the needle when you’re comparing sapphires.
Colour matters more than any other factor for sapphire, and it’s judged on three things at once: hue (the actual colour), saturation (how vivid it is), and tone (how light or dark). A sapphire that’s too dark can look almost black under indoor lighting, while one that’s too light can look washed out. The most prized blue sapphires sit in a rich, velvety medium-to-deep blue with strong saturation, sometimes described in the trade as “cornflower” or “royal” blue.
Clarity matters, but differently than it does for diamonds. Sapphires naturally form with internal characteristics called inclusions, and a completely flawless sapphire is genuinely rare. What matters is whether those inclusions are visible to the naked eye and whether they affect the stone’s brilliance, not whether they exist at all under magnification.
Cut determines how well the stone returns light to the eye. A well-cut sapphire, proportioned to work with its specific rough shape rather than forced into a standard template, will look brighter and more alive than a poorly cut stone of the same underlying quality.
Carat weight affects price the way it does with any gemstone, but sapphire’s density means it doesn’t wear its size quite the way a diamond does. Two sapphires of the same carat weight can look noticeably different in size on the finger depending on how they’re cut.
Treatment and origin are the two factors buyers ask about least and should ask about most. The vast majority of sapphires on the market today are heat-treated, a widely accepted industry practice that improves colour and clarity permanently and doesn’t need to be a red flag, but it does affect value, and a reputable jeweller should tell you plainly whether a stone has been treated. Origin also carries weight in the trade: sapphires from Kashmir, Myanmar (Burma), and Sri Lanka (Ceylon) each carry their own reputation and price expectations, though plenty of excellent, more accessible sapphires come from Madagascar, Australia, and Thailand too.
September’s Other Birthstone (and Its Birth Flower)
If you dig into birthstone charts, you’ll occasionally find lapis lazuli listed as an alternative or historical september birthstone, particularly in older or Tibetan-derived lists. Lapis is a deep blue metamorphic rock flecked with gold pyrite, closely tied to ancient Egyptian and Mesopotamian jewellery, and while it’s softer and less common in modern fine jewellery than sapphire, it’s worth knowing about if you come across it while gift shopping.
September also has its own birth flower, most commonly listed as the aster (sometimes alongside morning glory), a flower associated with love, wisdom, and patience, themes that line up neatly with sapphire’s own traditional meaning. It’s a nice detail to know if you’re building a gift around a September birthday rather than jewellery alone.
Caring for a Sapphire in Bali’s Climate
Sapphire’s hardness makes it fairly forgiving, but Bali’s climate still deserves a mention. Between the humidity, sunscreen, salt water, and sand that come with daily life on this island, fine jewellery works harder here than it does almost anywhere else. Rinse a sapphire ring in fresh water after swimming in the sea or a pool, since salt and chlorine can dull the metal setting over time even though they won’t damage the stone itself. Take rings off before applying sunscreen or lotion, since the residue builds up around the setting and behind the stone, and a soft brush with warm water and mild soap is usually enough to bring the shine back. If you want the fuller version of this, including how it applies to other coloured gemstones and metals, it’s worth reading our guide to caring for fine jewellery in Bali’s tropical climate.
Finding a September Birthstone Piece in Seminyak
If you’re in Bali and looking for a genuine sapphire, whether that’s an engagement ring, a birthstone gift, or simply a piece that catches your eye, it helps to buy from somewhere with real depth in coloured stones specifically, rather than a general jewellery counter that treats sapphire as an afterthought next to diamonds.
Jemme Jewellery, on Jalan Petitenget in Seminyak, is built around exactly that specialism. It holds Bali’s most extensive coloured gemstone collection, with vivid sapphires and rubies alongside rarer stones like peridot, morganite, and turquoise, set by a team with over 15 years of craftsmanship behind them. For an engagement ring built around a september birthstone, or a sapphire ring in Bali chosen as a gift for yourself or someone else, that combination of scale and genuine expertise is hard to find elsewhere on the island.
The boutique is open 10am to 10pm daily at Jl. Petitenget 28, Seminyak. You can browse the coloured gemstone collection and engagement ring options in person, or reach the team on WhatsApp at +62 813-5378-7156, by phone at +62 (0) 361 4733508, or by email at info@jemmebali.com to ask about a specific stone before you visit.
Final Thoughts
The september birthstone is sapphire, but that single fact undersells a stone with a genuinely rich history, a colour range far beyond blue, and a hardness that makes it one of the most practical choices for jewellery you intend to wear for decades. Whether you’re shopping for a September birthday, building an engagement ring around something other than a diamond, or just curious what the fuss is about, sapphire rewards a closer look. And if that closer look happens to take place in Seminyak, you’re standing in one of the better places in Bali to actually see what a fine sapphire looks like in person.