Sapphire Crystal Explained: Why It's Worth the Extra Cost

Look at the glass on a watch and you're looking at the single most scratched part of any timepiece. Sleeves, desks, door frames, car keys the watch face touches all of it, daily, for years. What that glass is made of decides whether your watch still looks new in year three or looks worn after month three.

What Sapphire Crystal Actually Is

Sapphire crystal isn't glass in the traditional sense it's synthetic corundum, the same mineral family as natural sapphire, grown in a lab and cut into a lens. On the Mohs hardness scale, sapphire crystal scores a 9, second only to diamond at 10. That's why it's the material of choice for watches designed to last, rather than watches designed to be replaced.

What Cheaper Watches Use Instead

Most watches under £150 use mineral glass, which scores around 5 on the same scale closer to a kitchen glass than a gemstone. Mineral glass is fine for a season, but it picks up fine scratches from ordinary contact with fabric, keys, or a desk edge within months. Some budget watches use plain acrylic, which scores even lower and scratches almost on contact.

Sapphire vs Mineral Glass: Quick Comparison

	Sapphire Crystal	Mineral Glass
Mohs hardness	9	~5
Scratch resistance	Extremely high	Low to moderate
Clarity over time	Stays clear for years	Dulls with micro-scratches
Typical price point	£300+	Under £150
Shatter resistance	Lower than mineral (more brittle)	Higher

The One Trade-Off

Sapphire crystal is harder, but that hardness comes with slightly more brittleness under a direct sharp impact mineral glass flexes a little more before it fails. In practice, for everyday wear, the scratch resistance of sapphire far outweighs this trade-off, which is why it remains the standard in watches built above the £300 mark.

Every Tomell London watch is fitted with sapphire crystal glass as standard, alongside a 316L stainless steel case and Japanese quartz movement no mineral glass, no compromise, regardless of which collection you choose.

Frequently Asked Questions

Can sapphire crystal still scratch?
Only from materials harder than it, such as another sapphire or a diamond. Everyday contact keys, desks, fabric won't mark it.

Does sapphire crystal affect how the dial looks?
Sapphire crystal is naturally clearer than mineral glass and often includes anti-reflective coating, so the dial typically looks sharper and more legible under direct light.

Is sapphire crystal harder to replace if it does break?
It's more specialised to source and fit than mineral glass, which is part of why it's reserved for watches built to avoid ever needing that repair in the first place.

How do I know if a watch actually has sapphire crystal?
Reputable brands state it explicitly in the specification. If a listing only says "scratch-resistant glass" without naming the material, it's very likely mineral glass, not sapphire.