Peridot and Spinel: Everything to Know About the August Birthstones
If someone asked you to name August's birthstone, you’d probably say peridot without thinking twice, that bright, lime-green stone that shows up in rings and pendants every summer. What most people don’t know is that August actually has two birthstones, and the second one has a backstory stranger than anything you’d expect from a gem you’ve probably never heard of.
So what is spinel? For centuries, it was mistaken for one of the most famous gems in the world, and it’s only in the last decade or that jewelers and buyers alike have started to understand what it actually is. Before getting into that story, it helps to understand why August ended up with two birthstones in the first place, and what actually separates them.
What Is the August Birthstone? Peridot and Spinel Explained
Peridot has held the peridot birthstone title for centuries, and it gets its color from iron within the crystal itself, which is why it always shows up as some shade of green, the classic August birthstone color most people picture. Spinel is the newer addition, an official spinel birthstone formally recognized by the American Gem Trade Association in 2016, and it occurs in a much wider range of colors, from deep red to soft lavender. They’re two genuinely different stones with two different stories, not one gem standing in for the other, so it’s worth understanding each on its own terms, starting with the one you already know.
Where Natural Peridot Comes From, and What Makes It Gem Quality
So what is peridot, exactly? It has an origin story unlike most other gemstones. It doesn’t form in the earth’s crust the way sapphire or emerald does. Instead, it forms deep in the upper mantle and reaches the surface through volcanic activity, which is part of why it’s sometimes called the volcano gem. Most of today’s supply comes from Arizona’s San Carlos Apache Reservation, along with material from Pakistan and Burma.
That volcanic origin also explains why judging quality is fairly straightforward. Because peridot only occurs in one color family, from a lighter lime to a deep, saturated olive, everything comes down to how pure and vivid that green actually is. A gem-quality peridot shows a clean, rich color without the brownish or muddy tone that lower-grade stones often carry, which makes comparing loose peridot stones side by side easier than it is with most other gems.
This peridot in our collection is a good example of that clean, saturated color.
There’s one more thing worth knowing before you buy: natural peridot for sale is almost always untreated. Its color comes from the stone itself, not from any heat or enhancement process, so a well-sourced peridot should come with that stated plainly, not left as a question mark. That kind of straightforward, natural character is exactly where peridot and spinel start to have something in common, even though spinel’s path to becoming a birthstone looked nothing like peridot’s.
Why Spinel Was Mistaken for Ruby for 500 Years
Here’s the part of the story most people find genuinely surprising. One of the most famous “rubies” in the world, the Black Prince’s Ruby, set in the British Imperial State Crown, isn’t a ruby at all. It’s a spinel. For hundreds of years, nobody had the tools to tell the difference, since spinel and ruby can form under similar conditions and end up looking remarkably alike. It wasn’t until modern gemological testing came along that the mix-up was caught, which means a fair amount of what history called ruby was actually spinel wearing the name.
That mistaken identity is also why spinel spent so long without a public identity of its own, and its color range is a big part of what makes that history worth setting right. As a spinel stone, its palette runs from hot pink spinel and soft gray through to a pale lavender that’s become a favorite among collectors and jewelry designers looking for something unexpected. Red spinel and blue spinel tend to be the most sought after, but this lavender spinel has its own quiet appeal for anyone who wants a stone that doesn’t look like everything else on the shelf.
There’s a practical upside to spinel’s history too, one that connects right back to what makes peridot appealing. Loose spinel for sale is usually untreated, meaning it reaches its full color naturally, without the heat treatment that’s routine for most ruby and sapphire on the market. In a category where enhancement is the norm rather than the exception, that’s a meaningful difference, and one worth asking about directly if a listing doesn’t already say so. This natural spinel is a solid example of that untreated character.
Choosing Between Peridot Rings and Spinel Jewelry
With both stones’ stories in mind, the choice between them really comes down to what you’re looking for. If you want a bright, dependable green that reads unmistakably as August birthstone and fits comfortably into everyday jewelry, peridot jewelry, rings especially, is the classic, accessible choice. If you’re drawn to something rarer, harder wearing, and less commonly seen, spinel gives you a wider color palette and a genuinely interesting story to go with it. Plenty of people end up choosing both, especially in a two-stone design that lets each gem stand on its own.
What to Check Before You Buy Loose Peridot or Spinel Online
Whichever stone you’re drawn to, the same handful of things matter once you’re actually ready to buy. Ask whether the gem is natural, not lab-created or simulated. Ask whether it’s been treated in any way, and expect a straight answer either way. Look for a listing that shows you a photo of the actual stone you’d receive, not a stock image meant to represent a stone like this one. And ideally, that stone should have been evaluated by a gemologist trained specifically in colored stones, someone with a GIA Graduate Gemologist credential rather than a diamond-only certification. That kind of transparency is really the whole point of buying a natural gemstone in the first place, whether it’s the peridot gemstone everyone recognizes or the spinel gemstone almost nobody does yet.
Frequently Asked Questions
Is peridot or spinel more valuable?
It depends on the individual stone. Large, richly colored peridot can be quite valuable, but fine, untreated spinel, especially in red, pink, or cobalt blue, has become increasingly prized by collectors and can be rarer per carat than peridot of similar size.
Is spinel a real birthstone, or just a substitute for peridot?
Spinel is an official August birthstone in its own right, added by the American Gem Trade Association in 2016. It isn’t a stand-in for peridot; the two are recognized side by side for the same month.
Does natural peridot need special care?
Peridot holds up well in everyday jewelry, but it’s best cleaned with warm, soapy water rather than an ultrasonic cleaner, and it’s worth avoiding sudden temperature changes or long stretches in direct sun.
Is spinel typically treated or enhanced?
Most gem-quality spinel sold today is untreated. That sets it apart from ruby and sapphire, which are commonly heat-treated to improve color, though any treatment, however minor, should always be disclosed by the seller.
Is spinel a good alternative to sapphire?
For many buyers, yes. Spinel offers a similar range of rich color, particularly in blue and pink tones, along with real hardness and durability, often at a more accessible price point and usually without the heat treatment that most sapphire undergoes.
Explore our August Birthstone collection to see the peridot and spinel we currently have in stock, each one individually photographed and evaluated by our GIA Graduate Gemologist before it’s listed.
