The two Carrera family watches in this article are two of the most expensive timepieces TAG Heuer has ever produced. There is no doubt that these two “Plasma Diamant” watches are strange and very expensive, but they are also extremely rare and interesting manifestations of modern luxury watches. This journey began back in 2022 when the brand released the TAG Heuer Carrera Plasma Tourbillon Nanograph (Ref. XCBN5A90.FC8315). This took the 44mm wide Carrera Chronograph case concept and transformed the historic sports watch style into something a lot more decorative and modern. The viewer was meant to notice the large asymmetrically set baguette-cut diamonds put into the matte black case, the machined diamond crown, the baguette-cut diamond hour markers, and of course the diamond texture face. The watch used a more traditional polished black ceramic tachymeter-style bezel and watch matched to a simple black strap. The price of the watch was set at a staggering 350,000 Swiss Francs.

Only a year later in 2023, TAG Heuer upped the ante on the same concept considerably by debuting the even more elevated TAG Heuer Carrera Plasma Diamant d’Avant Garde (Ref. CNBN5A91.BZ0000). Keeping the same movement and 44mm wide black aluminum case, the TAG Heuer Carrera Plasma Diamant d’Avant Garde took the concept in a more jewelry-style direction by adding a black bezel and bracelet that were likewise set with the large lab-grown diamonds for a much more bold and interesting decorative effect. The price reached CHF 500,000 and a while ago, we went hands-on with that upgraded version. Building on that review, I offer my take on the watches and how people may want to think about them.

Several years ago in 2019, TAG Heuer introduced a new mainspring technology called Isograph. The technology was supposed to be a carbon-based alternative to silicon mainsprings in watches, to replace more historically metal mainsprings. Non-metallic hair/balance springs are resistant to magnetism and have only benefits over metal such as lower friction and some other advantages. Isograph hairsprings were produced in-house by LVMH and were intended to outfit the lower-priced Autavia collection of TAG Heuer timepieces. The only problem was the Isograph wasn’t quite ready for industrialization. While the technology worked, it proved difficult to mass produce the hairsprings, and the idea of putting them in mainstream TAG Heuer watches needed to be shelved. The Isograph name has seemingly been changed to Nanograph, and we see that TAG Heuer still likes to use the technology for higher-end watches where it can spend more money on the movement. Accordingly, both watches have what TAG Heuer refers to as “Carbon Tourbillons,” which are essentially the Heuer 02-T automatic chronograph movement mechanism with an Isograph/Nanograph hairspring.

The Heuer 02 and 02T automatic chronograph movements are pretty great, even if they aren’t exactly high horology. (If you are looking for that in a modern high-end TAG Heuer then the 2024 Monaco Split Second Chronograph is probably a better way to go.) The Heuer 02-T is a durable and accurate big chronograph movement that has been fitted with a tourbillon. It operates at 4Hz with 65 hours of power reserve and is a COSC-certified Chronometer. I really like this movement, but I need to remind folks that it was originally designed to be not in a very high-end watch, but rather an entry-level Swiss Made tourbillon. The first TAG Heuer Carrera Tourbillon, the TAG Heuer Carrera Chronograph Tourbillon, was priced at around $15,000 USD. Today, the cost of TAG Heuer’s entry-level Carrera Tourbillon watches is around $25,000 USD. True Swiss Made tourbillon watches (without a chronograph or COSC certification) are now available for as low as about $6,000 USD. In any event, even though the Heuer 02T was never meant to be in such high-end movements, it is a very reliable performer, and for these Carrera Chronograph Plasma Nanograph Tourbillon watches the movements are given some extra decoration and the carbon hairsprings.

But these two models up the ante with their lab-grown crystals, sourced through a collaboration between TAG Heuer and Capsoul. Similar to the popularity of synthetic sapphire crystal, many in the watch industry agree that there is a bright future for creative use of lab-grown diamonds. Such uses are intended not only for decorative purposes (polished and facet-cut stones) but also for other applications where diamond as a material could be useful and playful. A good example is the crowns of these watches which begin as large grown diamonds and are then machined into the shape of a crown. This is a very complicated process and TAG Heuer has now introduced these crowns (in other colors as well) to some of its other “Plasma” watches in both pink and yellow.

While the original model had an aluminum case with a more traditional black ceramic chronograph bezel, the new D’Avant Garde throws out all notions of subtlety and restraint. The new model instead sees aluminum used for the entire construction: case, bezel, and bracelet. Using this material is what presumably allows for setting the entire thing with diamonds (a process completed by Geneva-based specialist Salanitro), with the bracelet featuring a waterfall effect as the frequency of diamonds diminishes around the wrist. While TAG went outside for most of the diamond work, it chose to cut and mount the crown diamond in-house.

Both the TAG Heuer Carrera Tourbillon Nanograph Plasma Diamant D’Avant Garde and the TAG Heuer Carrera Plasma Tourbillon Nanograph which came before it are incredible timepieces to behold. They aren’t exactly pretty in a traditional sense, but they are fun, spirited, and eye-catching. For me, the most shocking this is the price, especially given how many distinct parts of these watches were never meant to be price-toppers. The Nanograph technology, lab-grown diamonds, and the Heuer 02T movement are all things that are meant to deliver excellent value. No doubt these require huge amounts of time to make and develop, but I just wonder if TAG Heuer missed part of the story when trying to reconcile all of these concepts with the enthusiasts who have been following the brand’s developments over the last decade or so.

People like categorizing watches, but unfortunately these two TAG Heuer Carrera Tourbillon Nanograph Plasma watches are difficult to define or neatly put into any one category. These are certainly not traditional jewelry watches or those whose values are derived from precious materials or formal wearing value. These also aren’t sports watches on account of the price point and material choices, despite the obvious sports watch profile and movement choice. Yet, despite the fiddly nature of how these watches fit into the scheme of modern horology, they are fun in a sort of irreverent, irresponsible way. It is also a bit funny that TAG Heuer cannot seem to put “diamond” in the name of the watches even though diamonds (natural or lab-grown – they are chemically the same) are clearly a bit part of the theme. Instead, they use the much more vague “plasma” term. Burning plasma is clearly part of the diamond formation creation process, but I am not sure the majority of consumers will make that connection. Perhaps watches like these are so rare that TAG Heuer doesn’t care. Neither for instance, are found in TAG Heuer’s standard online product catalog.

The best thing about these two wild TAG Heuer Carrera Tourbillon Nanograph Plasma watches is the conversations they can inspire. Put a bunch of watch nerds into a conversation with their opinions about these products, and emotions will fly all over the place. That suits TAG Heuer just fine so long as people still consider most other Carrera watches conservative, good-value timepieces. For the rare few there is the TAG Heuer Carrera Plasma Tourbillon Nanograph (Ref. XCBN5A90.FC8315) priced at CHF 350,000 and the TAG Heuer Carrera Tourbillon Nanograph Plasma Diamant D’Avant Garde (Ref. CNBN5A91.BZ0000) priced at CHF 500,000. Learn more at the TAG Heuer website here.