Acrylic Crystal A Staple in Watchmaking History

When admiring your timepiece in sunlight, have you ever considered the transparent material protecting the dial? Not all watch crystals are made of scratch-resistant sapphire—many feature acrylic glass, a material steeped in horological history.

Acrylic glass, also known as PMMA (polymethyl methacrylate), was first developed in Germany in 1931. Originally prized by the aviation industry for its remarkable properties—weighing half as much as mineral glass while offering 17 times greater impact resistance—it became the material of choice for aircraft windshields. By the late 1930s, watchmakers began adopting this synthetic resin for timepiece crystals in both wristwatches and pocket watches.

While "Plexiglas" remains a registered trademark of German chemical company Evonik, the watch industry typically refers to the material as "acrylic crystal" or "reinforced acrylic glass." Compared to modern sapphire crystals, acrylic demonstrates lower scratch resistance and may develop a yellowish patina over decades of use. However, its shatter-resistant nature and ability to be polished—removing minor scratches with relative ease—make it a practical choice for many collectors.

Beyond functionality, acrylic glass carries distinct aesthetic appeal. Its warm, slightly distorting optical qualities and vintage glow continue to captivate watch enthusiasts, particularly those drawn to historical timepieces or modern watches with retro styling.

Today, acrylic maintains its niche in watchmaking, serving both as a practical solution for certain tool watches and as a deliberate stylistic choice evoking horological heritage. More than just protective material, these crystals represent a tangible connection to watchmaking history—a transparent window into the past that continues to find relevance in contemporary timekeeping.