Welcome to Watches You Should Know, a biweekly column highlighting little-known watches with interesting backstories and unexpected influence. This week: the Rado Diastar.
The offbeat design of the Rado DiaStar isn’t the only reason it should get your attention. It’s funky, for sure, but you might not guess that it was technologically visionary. As ceramics and material innovation have become some of the most important current areas of competition among major watch brands, the DiaStar’s introduction in 1962 represents a milestone for the industry that today seems all the more significant. Rado introduced the DiaStar as “the world’s first scratchproof watch,” and the brand today quietly continues to be a leader in technical materials.
The DiaStar was long considered the “first ceramic watch,” but there has subsequently been some confusion since the material was tungsten carbide rather than the more common form of watchmaking ceramic, zirconium dioxide. The first this, the first that…These are important designations watch companies use to stake their place in history, but there’s often some controversy and discrepancy surrounding such claims. The Rado DiaStar is one such example that deserves some clarification. The DiaStar is indeed tungsten carbide, but that doesn’t mean it wasn’t the first ceramic watch.
It turns out that the definition of ceramic isn’t so cut-and-dry, as ceramic is more like a type of material than a specific substance. Naturally, the “high-tech ceramic” used for watchmaking is different than that of your coffee cup, which helps illustrate the wide variation possible in ceramics. According to Wikipedia, “a ceramic is an inorganic, nonmetallic solid material comprising metal, nonmetal or metalloid atoms primarily held in ionic and covalent bonds.” There’s a lot to unpack there, but, essentially, ceramic can be made from a range of elements, including metals like tungsten.
So, is tungsten-carbide a ceramic? It seems that the American Ceramic Society, at least, considers it so, which is good enough for this non-chemist watch enthusiast to call the DiaStar the first ceramic watch.
It’s true, however, that most ceramic in watches today use a different compound. You can even find ceramic watches with ZrO2 proudly printed on their dials (for zirconium dioxide). No matter how you look at it, the Rado DiaStar was a unique and notable achievement. Tungsten carbide has been used in very few other watches, and more brands didn’t start making ceramic watches until the 1980s. Now, everybody’s doing it.
Scratch-resistance is an important part of what has helped make ceramic the new premium material of watchmaking. Indeed, the cases of many vintage DiaStar models still look essentially brand new. Sport watch bezels with aluminum inserts used to be standard, but they’ve now begun to feel inferior as ceramic has generally replaced them for use by luxury brands, from Rolex to Omega and many more.
Fully ceramic-cased watches, on the other hand, entail a whole other level of cost and complexity, but brands clearly consider them a worthwhile investment. While ceramic can chip or crack with very hard impacts, it’s valued for its scratch-resistance and lightweight properties, as well as for having a deservedly technical and exotic attraction. Excitingly, it also offers the the use of colors without coatings: For a long time, it was exceedingly difficult for watch manufacturers to produce ceramic in colors other than black and white with sufficient consistency and accuracy of hue, but Rado is again leading the way with the likes of its new Le Corbusier collection.
Ceramic in watchmaking didn’t really pick up until the 1980s, and the technology has really only getting off the ground in the last few years. Nowadays, just about every major brand seems to include a fully ceramic-cased watch in its catalog. (Even the Apple Watch comes in a premium version with a ceramic case option.) The 1962 DiaStar also used sapphire crystal far before it became the standard for luxury watch crystals that it is today. Ceramic bezel/case and sapphire crystal together give a watch an essentially unscratchable facade.
Ceramic is still a core part of Rado’s identity. The DiaStar came out almost 60 years ago, and Rado still offers it in a pretty true-to-original form, though with some different nomenclature. (Now the collection is named the Original, even though “DiaStar” still features prominently on the dial.) Its tungsten carbide case material is referred to as “Hardmetal” to differentiate it from its other watches that are High-Tech Ceramic, Plasma High-Tech Ceramic, and Ceramos (the alternate term “hardmetal” for tungsten carbide is standard but might be a little confusing). Of course, Rado also makes watches in stainless steel.
The DiaStar is aesthetically — shall we say — not for everyone. But knowing its place in history might change the way you look at it. The DiaStar being a somewhat overlooked watch is good news for vintage buyers who can appreciate its quirks, but Rado’s achievements deserve greater recognition, and every fan of watchmaking and material innovation should understand its significance.