Sapphire, Mineral, and Acrylic Crystals Compared

The crystal is the transparent cover over the dial, and it is the part of a watch that takes the most daily abuse. The material changes how scratch resistant the watch is, how it looks, and what it costs to repair.

Sapphire crystal is synthetic sapphire, one of the hardest materials available after diamond. It resists scratches extremely well, which is why it is standard on most watches from the mid-range upward. Its downsides are that it can shatter on a hard impact and it reflects more glare unless it has an anti-reflective coating.

Mineral crystal is hardened glass. It is cheaper and more resistant to shattering than sapphire, but it scratches more easily. It is common on affordable watches and works well if you are careful or do not mind a little wear.

Acrylic, often called Plexiglas or hesalite, is a plastic. It scratches easily, but the scratches can be polished out in minutes with a bit of polishing paste, and it is very shatter resistant. Many fans of vintage-style watches prefer acrylic for its warm look and the way it distorts the dial slightly at the edges.

You may also see a domed crystal, which curves up over the dial and adds a vintage feel, and a flat one, which looks modern and reduces distortion. Some sapphire crystals have anti-reflective coating on one or both sides, which makes the dial easier to read at an angle.

A good rule of thumb: choose sapphire for a watch you wear daily and want to stay looking new, mineral for a budget watch, and acrylic if you love the vintage character and enjoy the ritual of polishing.

Check the specs on any watch you are considering. If crystal type matters to you, confirm it with the maker, since the same model can come in different versions.