Before we get into the nuances of the black ceramic Royal Oaks, of which the Double Balance Openworked is just the latest, a quick primer on ceramic: Ceramics are essentially materials composed of minerals and binder that are heated at very high temperatures until their chemical compositions become a glass-like solid. Humans have been making ceramics for over 25 millennia, with the earliest earthenware pots going back to before 24,000 BC.

The modern ceramics used in watchmaking adhere to this basic definition, but they’re a far cry from those used to make dishes and vases. They’re modern compounds called oxide ceramics that can be used to replace metals, and that have much greater resistance to cracking and scratching. Audemars Piguet uses a ceramic with a combination of zirconium oxide and yttrium oxide as the base. (Zirconium oxide ceramics are the most common in high-end watches.)

IWC was the first watch brand to create a ceramic-cased watch, with the Da Vinci Perpetual Calendar circa 1986, and it continued to innovate in that area, in 1994, releasing the famous ref. 3705, the first ceramic chronograph. From there, we’ve seen a long line of ceramic watches, including the famous Chanel J12 (which was one of the first to use a ceramic bracelet) and Omega’s ceramic Seamasters and Dark Side of the Moon Speedmaster, which even use ceramic for the dials. You can dig deeper if you really want to go down a rabbit hole, and find ceramic parts being used in movements because of the material’s lower coefficient of friction versus metal, its stability across temperature ranges, and its durability.

I have tried to figure out the very first time that Audemars Piguet utilized ceramic and can’t seem to nail down a true first foray. It started at least a decade or so ago, with special iterations of the Royal Oak Offshore with ceramic components and then the Royal Oak Offshore Diver models with black and white ceramic cases. These Divers were the genesis of the current ceramic Royal Oaks, particularly in the finishing of the ceramic. Typically, you’d find black ceramic either fully polished or given a matte, sandblasted finish. In contrast, AP applied a vertical brushed finish for the Diver’s case, giving it a bit of a metallic look that set it apart from other ceramic watches. That was just the start.

“Eight years ago, we were making ceramic bezels and cases, but when I took over the CEO position, I imagined a ceramic bracelet because I thought it would be ideal,” says François-Henry Bennahmias, CEO of Audemars Piguet. “The answer I got was that it was going to be impossible. It’s too complicated; it would take forever. I said, listen, I’m only 48 years old, so we have all the time to get it done. It’s going to be unbelievable.”

Audemars Piguet caused a huge stir at SIHH 2017 when they dropped the Royal Oak Perpetual Calendar in black ceramic. Nobody had ever seen a watch quite like this before, and AP, the masters of hype that they are, handled the release deftly. They didn’t make too big a fuss, instead letting the collector community and watch-loving celebs create the excitement for them. This became a model for most of their releases since then (a certain new family of watches notwithstanding).

Since then, we’ve seen four other all-black-ceramic Royal Oaks join the collection: the Perpetual Calendar Openworked, the Tourbillon Extra-Thin, the Tourbillon Chronograph Openworked, and, as of a few weeks ago, the Double Balance Wheel Openworked. There have also been quite a few Offshore models with black ceramic cases and even an all-white-ceramic Royal Oak Perpetual Calendar too.

These watches are all complicated and expensive. At a hair over $80,000, the Double Balance Wheel Openworked is the most affordable of the non-Offshore models (which are a bit of a different beast and don’t have ceramic bracelets), and the only one under the six-figure mark. All of this despite it being almost four times the price of a standard, time-and-date Royal Oak in stainless steel.

“This watch is a product of the constant pursuit of perfection in open-working, hand-finishing, avant-garde design, and material innovation, and I’m all for it,” says Austen Chu, an Audemars Piguet collector and the founder of Wristcheck (you might know him as @horoloupe on Instagram). “Open-working is one of the hallmarks of AP, and what they’ve done with it here shows how creative and talented watchmakers are when they’re passionate about their craft.”

So far, the black ceramic Royal Oaks have all been limited edition and “limited production” watches, and all but the Tourbillon Chronograph Openworked are exclusive to Audemars Piguet’s own boutiques. This means they’re hard to get. Like, really hard to get. You need to be an existing customer with an AP boutique, and a good one at that. If you’re walking in off the street, hoping to buy your first Royal Oak, even a duffel bag stuffed with $80,300 in non-sequential unmarked bills can’t help you.

Because “limited production” is a nice way of saying, “We’re only making a few, and we’re not saying how many,” it’s tough to know how rare these watches actually are. Demand is so high, even at those prices, that AP could likely make a relatively large quantity and still maintain waitlists. I asked Bennahmias if he could share any production figures, and after demuring and saying that he couldn’t really share too much, he did offer one very helpful detail: With the launch of the Openworked Perpetual Calendar, production will cease on the original Perpetual Calendar, and AP will have made just over 600 examples of the original black ceramic Perpetual Calendar when everything is said and done.

That’s still pretty damn rare, especially when you consider it in the context of AP’s overall production numbers. Audemars Piguet makes about 40,000 watches per year and launched the ceramic QP in January 2017. That means about 160,000 watches have left the factory over that four-year span. Of that, just one-third of one percent are black ceramic Royal Oak Perpetual Calendars.

“If you’ve ever handled a full ceramic bracelet, you’ll know exactly why these watches get so much attention,” says Chu. “The sheen and attention to detail on the case and bracelet on the black ceramic Royal Oaks are second-to-none in terms of both aesthetics and comfort.”

The attention to detail that Chu refers to here is the unusual way in which AP finishes the cases and bracelets of these watches, as if they were metal. You’ve got brushed surfaces, with even, vertical lines, contrasting with highly polished edges on the bracelet links and the outer facet of the bezel. Achieving this level of detail is extremely difficult when working with a hard material like ceramic, but it visually connects these Royal Oaks to the generations before them, and it’s a treatment unique to Audemars Piguet.

When I asked Rebecca Ross, a watch specialist at Christie’s, if she thought these watches would have long-term appeal to collectors, she brought up something I’d never considered before: the way they will age. “The loss of material over time that one might notice on a gold watch, for example, will not occur with ceramic,” she said. When it comes to vintage Royal Oaks, this is a huge deal. The appeal of the watch is almost entirely in its sharp geometry and careful finishing. If edges start to round and brushed surfaces dull, the watch loses its je ne sais quoi in a big way. With these ceramic editions, that’s all but impossible.

So are we going to keep riding this black ceramic wave for another few years? There’s so much ground left to be explored here, and so much pent-up demand, that I can’t see black ceramic disappearing anytime soon. Just imagine, for instance, how covetable a black ceramic Jumbo would be.

That said, I think we’re primed for a new material to take over the zeitgeist. What do you think it’ll be? A new high-tech material? A proprietary gold alloy? Let me know what you think down in the comments below. Your guess is every bit as good as mine.

When I asked Bennahmias whether ceramic was going to be a long-term mainstay at Audemars Piguet, a blunt and honest, “I don’t have a clue” was his answer. “We have always been about materials, especially with the Royal Oak. Ceramic was just another adventure toward what we could use and what materials we could play with … We will keep chasing the grail of coming up with new materials that can make a stand in the world of high-end watchmaking. Twenty or thirty years from now, we might use materials that repair themselves. Who knows?”