Sapphire, Mineral or Acrylic Glass: Which Watch Crystal Should You Choose?

A watch crystal can be made of sapphire, mineral glass or acrylic glass, three materials that offer neither the same scratch resistance nor the same behavior under impact. Sapphire is by far the most scratch-resistant, mineral glass offers a good balance between durability and cost, while acrylic, rarer today, appeals mainly for its vintage character.

Sapphire Crystal, the Benchmark for Resistance

Sapphire crystal is in fact synthetic corundum, an extremely hard material that can only be scratched by diamond or another sapphire. It is the preferred choice on high-end watches, as it retains perfect transparency over the years, free of the micro-scratches that dull a dial's appearance. Its hardness does come with a trade-off, however: in rare cases of a severe impact, it may crack rather than scratch, where a softer crystal would simply have marked on the surface.

Mineral Glass, a Solid and Accessible Compromise

Mineral glass is heat- or chemically-treated glass designed to reinforce its resistance, without reaching that of sapphire. It nonetheless remains noticeably more scratch-resistant than ordinary glass, and has the advantage of being more flexible under impact, making it less prone to cracking. It is a sound choice for demanding daily wear, where the slight patina it takes on over time is also part of the charm of a regularly worn watch.

Acrylic Glass, Between Lightness and Retro Spirit

Acrylic glass, or plexiglass, is a very lightweight transparent plastic that rarely breaks, as it absorbs impact by flexing slightly rather than shattering. It does, however, scratch far more easily than mineral glass or sapphire. It is mainly found on pieces with a deliberately vintage spirit, where its slightly domed texture fully contributes to the watch's character.

At Maison Montignac, the standards of our Besançon workshop guide material choices at every stage of design, in keeping with our two-year warranty. Browse our latest releases or discover our watches to find the piece that suits your needs.