When it comes to buying a watch, many people focus on the movement, brand, or strap. However, one of the most important components—often overlooked—is the watch glass. Also known as the crystal, the watch glass protects the dial and hands, and plays a critical role in both the appearance and durability of a timepiece. There are three main types of watch glass: sapphire, mineral, and acrylic. Each type has its own characteristics, benefits, and drawbacks. This guide will help you understand the differences so you can make an informed decision based on your needs and preferences.

1. Sapphire Crystal

What is Sapphire Crystal?

Sapphire crystal is a premium material used in high-end watches. Despite its name, it’s not made from natural sapphire gemstones. Instead, it’s a synthetic version created in laboratories by crystallising pure aluminium oxide at extremely high temperatures. The result is a clear, incredibly hard substance that’s second only to diamond on the Mohs scale of mineral hardness.

Advantages

• Superior Scratch Resistance: Sapphire is extremely hard, which makes it highly resistant to scratches. You can wear a sapphire crystal watch daily, and it will likely remain pristine for years.

• Clarity: Sapphire crystal offers excellent optical clarity, especially when treated with anti-reflective coatings. This ensures the dial remains easy to read in various lighting conditions.

• Prestige: Watches with sapphire crystals are often associated with luxury, quality, and fine craftsmanship.

Disadvantages

• Price: Sapphire crystal is expensive to produce and contributes significantly to the cost of a watch.

• Shatter Risk: While it’s hard to scratch, sapphire can be brittle. A strong impact can cause it to crack or shatter, especially if dropped on a hard surface.

• Repair Costs: Replacing a sapphire crystal can be costly, especially on luxury or rare models.

Best For:

• Watch collectors

• Daily wear in professional environments

• People looking for long-term clarity and minimal wear

2. Mineral Glass

What is Mineral Glass?

Mineral glass, also referred to as hardened mineral crystal or tempered glass, is regular glass that has been heat-treated or chemically strengthened to improve durability. It is the most common type of watch glass used in mid-range and affordable timepieces.

Advantages

• Affordability: Mineral glass is significantly cheaper to produce than sapphire, making it a popular choice for manufacturers and consumers alike.

• Impact Resistance: It is less likely to shatter than sapphire, as it has more give and flexibility.

• Easy Replacement: If damaged, mineral glass can be replaced relatively easily and affordably.

Disadvantages

• Scratch Prone: Mineral glass is more susceptible to scratching than sapphire. Keys, coins, or even sandy environments can leave marks on the surface.

• Less Prestige: It doesn't carry the same luxury connotations as sapphire crystal.

Best For:

• Everyday wearers who want a balance between cost and durability

• Casual watches

• Sports watches that may be exposed to occasional knocks or bumps

3. Acrylic Crystal

What is Acrylic Crystal?

Acrylic is a type of plastic, also known as plexiglass or hesalite (a trade name used by brands like Omega). It is the most affordable and flexible option among the three types of watch glass. Although it might seem outdated in a world of high-tech materials, acrylic still has its place in the watch industry, particularly in vintage-style or military-inspired watches.

Advantages

• Lightweight: Acrylic is much lighter than both sapphire and mineral glass, making it ideal for large or bulky watches.

• Highly Impact Resistant: Acrylic doesn’t shatter easily. Instead, it tends to crack or dent, which can often be polished out rather than replaced.

• Warm Appearance: Acrylic can give a vintage, slightly domed look that adds charm and character to a watch.

• Affordable Repairs: Scratches can often be polished out at home using a polishing compound like Polywatch.

Disadvantages

• Scratches Easily: Acrylic is the softest of the three, and will pick up scratches from everyday use. Even fingernails or clothing zippers can leave marks.

• Lower Clarity Over Time: While new acrylic is clear, it can yellow or cloud over time, especially if not well cared for.

• Less Premium Feel: Acrylic watches don’t usually exude the same level of luxury or refinement.

Best For:

• Vintage watch lovers

• Field and military watch wearers

• Kids’ and beginner watches

• Those who prioritise repairability over long-term clarity

How to Choose the Right Watch Glass

The type of crystal you choose should depend on your lifestyle, budget, and personal preferences. Here’s a quick comparison to help guide your decision:

Feature

Sapphire Crystal

Excellent scratch-resistance

‍Moderate impact-resistance

Higher price

Heavy

More expensive to repair

Modern and sleek appearance

Mineral Glass

Moderate scratch-resistance

Good impact-resistance

Medium price

Medium weight

Moderate repair costs

Neutral appearance

Acrylic Crystal

Poor scratch-resistance

Excellent impact-resistance

Low price

Light weight

Low repair costs

Vintage and warm appearance

If you're looking for a luxury watch that will remain clear and flawless for years to come, sapphire is the best choice—provided you’re careful with how you wear it. If you want something affordable and versatile, mineral glass is a great middle-ground. And if you're drawn to vintage aesthetics or need a tough, lightweight watch, acrylic might be the way to go.

Final Thoughts

Understanding the differences between sapphire, mineral, and acrylic watch glass can help you choose a timepiece that best suits your lifestyle and expectations. No one type is objectively "better" than the others—it all depends on how you use your watch and what you value most: clarity, durability, affordability, or aesthetics.

Next time you’re shopping for a watch—whether it’s a rugged field watch, a dressy timepiece, or a vintage reissue—don’t just consider the dial and movement. Take a moment to check what kind of glass is protecting it. That small detail could have a big impact on how your watch looks and performs over time.

Contact us for advice on watch glass restoration.