Rolex Patents a New Colored Crystal — Milgauss Comeback Ahead?

Rolex has quietly secured a new patent that could signal the comeback of one of its most distinctive design details: the colored watch crystal. The discovery was first reported by researcher and watch spotter @niccoloy on Instagram, who noticed the filing shortly after it was granted on September 30, 2025.

A familiar idea, completely rethought

Image Source: Rolex

For collectors, the mention of a colored watch crystal instantly recalls the green-sapphire Rolex Milgauss, discontinued in 2023. That watch stood out in Rolex’s modern lineup for its optional green tint: a feature achieved through a complex process of coloring the sapphire crystal during its growth. It was eye-catching, categorically rare in the watch world, and difficult to reproduce at scale.

This new patent takes the same concept and makes it far more practical. Instead of coloring the entire sapphire boule during growth, Rolex’s new method colors only a thin surface layer. The result, according to the filing, is the same vivid appearance with more control, better consistency, and fewer manufacturing challenges.

What Rolex actually patented

Rolex's New Colored Glass Patent

The patent, filed back in February 2020, outlines a way to tint sapphire by introducing trace elements like cobalt, iron, or gold into its outermost layer, then heat-treating it until the color becomes part of the material itself. The process can produce blue, green, or even pink tones, all while keeping the crystal clear enough to read the dial beneath it. Rolex notes that transparency remains above 80 percent — high enough that lume and legibility aren’t compromised.

In simpler terms: Rolex can now make colored sapphire crystals more precisely, more consistently, and potentially in more colors than ever before.

Why this feels like groundwork for the Milgauss

Image Source: Hairspring

Rolex patents plenty of technology that never reaches production, but timing matters. The Milgauss — the brand’s science-themed model and the only Rolex ever sold with a colored crystal — has been absent from the catalog for two years. Past anti-magnetism patents have already sparked Milgauss speculation, and if Rolex does plan to bring it back, this new coloring technique fits perfectly. It would preserve the model’s signature visual quirk while improving how it’s made.

That doesn’t confirm a new Milgauss, of course. Rolex could apply the idea elsewhere — perhaps as a subtle accent on another professional model. But the patent makes one thing clear: colored sapphire isn’t a one-off experiment anymore. It’s something Rolex now has the tooling to do repeatably and at scale.

The takeaway

Spotted by @niccoloy, this newly granted patent gives Rolex a refined, production-ready way to create colored sapphire crystals. Whether it appears on a revived Milgauss or something entirely new, the technology revives one of Rolex’s most distinctive — and collectible — modern design ideas, and that alone is worth celebrating.

Header Image Source: Hodinkee