That circular piece of glass that sits on top of your watch dial deserves more credit. It has a role to carry out. It needs to be durable, needs to be able to shield the dial from scratches, knocks and bumps sustained during the rigours of everyday life. Have you considered watch glass types properly? If you haven’t decided on which watch glass type is best – you may want to now, since all you’ll ever need to know about watch glass is compiled in this short, easy-to-read article below. Grab a drink, sit back and read up on watch glass types – it could be more valuable than you think!

Sapphire Crystal glass – looks good, feels good, extra strong

Start at the top if you want a watch with the highest quality glass. Sapphire crystal glass is the strongest and most durable. With a hardness that is only trumped by diamond, synthetic sapphire is used (for its clear colour as opposed to genuine sapphire, which comes in a myriad of colours including red, blue, purple, green and yellow). Auguste Verneuil, a French Chemist originally birthed the concept of sapphire crystal glass. He created huge sheets of sapphire crystal by acquiring aluminium oxide. By subjecting it to extreme temperatures and blasting them with pressure, the powder turned to crystals which were then pressed into sheet-form.

Kaal watch domed sapphire crystal
The distinctive domed sapphire crystal of the Kaal Watch Multiverse

Watches with sapphire crystal glass fronts offer the best scratch resistance and are often treated with layers of anti-reflective treatment to grant the wearer a clear view into the dial. Since sapphire crystal glass is predominantly used in high-end watches, it often forms the back of a luxury watch. See-though case backs or transparent exhibition backs put the performance and arrangement of a mechanical movement on display through a sapphire crystal glass window. Sapphire crystal glass watch fronts also come in different shapes from slightly cambered lenses to boxed, domed and flat shapes.

Mineral crystal glass – harder than acrylic, weaker than sapphire crystal

Seiko Orange Monster
Seiko’s Hardlex is a type of mineral crystal

Probably the most commonly used material for a watch, mineral glass is used in mid-range designer watches. Standard tempered glass made from silica often forms mineral glass, making it more scratch-resistant. The material is fairly low-cost compared to sapphire crystal, but despite sustaining a few scratches after some wear and tear – some can be buffered out. Mineral glass, like sapphire crystal glass, can also be treated with anti-reflective technology. Often known as AR-coating or anti-glare treatment when displayed in a spec list, this quality will help to rid any undesirable glare affecting your view of the dial. It can also reduce the strain on your eyes from reflection and make the timepiece look more aesthetically pleasing overall.

Acrylic – easy to replace, cheap and lightweight

HKED Seagull 1963
The Seagull 1963 often has a domed plastic crystal

Acrylic is, in other words, plastic, so it’s understandably the weakest of all types of watch crystal. Whilst it won’t last as long as mineral or sapphire crystal glass, acrylic glass is a budget-friendly material for a budget-friendly watch (in other words, you get what you pay for). That said, one fact you may not be aware of is that Plexiglass is a type of acrylic glass. To disguise its association with acrylic, some luxury watch brands do use Plexiglass on some of their models. Acrylic glass is lightweight so it does have advantages in its own right. The material also goes by the name of Acrylite, Lucite and Perspex. Bottom line though – if you drop a watch with an acrylic front and it smashes, it won’t cost you an arm and a leg to replace, hence why it’s used in many kids watches, because, let’s face it – probably going to happen again… and again.

So, there you have it – a very simple guide to watch glass types. Think of it as a high-end, mid-range and low-budget hierarchy in terms of pricing and you can’t go far wrong!

By Nina Scally

Aside from juggling nappies, tantrums and failing at pastry-making, Nina has been writing for the luxury watch industry both as a hobby and for a living for the past 8 years. Writing to a male-dominated audience can be challenging at times. But she likes a challenge. Just not pastry.

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