会社のニュース Mineral Glass Vs Sapphire Comparing Watch Crystal Durability

Imagine your beloved timepiece acquiring unsightly scratches after an accidental bump, making time-reading increasingly difficult. The watch crystal, this seemingly insignificant protective layer, actually serves as the primary defense mechanism for the dial against external damage. While precision timekeeping remains paramount, selecting a scratch-resistant, clear crystal has become a focal point for watch enthusiasts.

Watch crystals, also known as watch glasses, serve as the transparent cover protecting the dial from dust, scratches, and other potential damage. Modern timepieces typically employ two primary crystal materials: hardened mineral glass and synthetic sapphire glass. These materials differ significantly in hardness, scratch resistance, and cost.

Hardened mineral glass isn't ordinary glass. Through a specialized thermal tempering process involving controlled heating and rapid cooling, the glass undergoes molecular restructuring that enhances both hardness and toughness. This tempering process creates compressive stress on the surface and tensile stress internally, significantly improving impact resistance while reducing the likelihood of shattering.

The primary advantage of hardened mineral glass lies in its cost-effectiveness, making it the preferred choice for mid-range timepieces. While less scratch-resistant than sapphire, it provides adequate protection against everyday wear and tear. The tempering process also reduces the risk of sharp fragment formation upon breakage, enhancing safety.

Sapphire crystal, despite its name, consists of synthetic single-crystal aluminum oxide (Al₂O₃) rather than natural gemstones. Manufacturers create this material through an intricate process: melting high-purity alumina powder, growing large single-crystal ingots using specialized techniques like the Kyropoulos or Czochralski methods, then precision-cutting and polishing the crystals into flawless transparent sheets.

With a Mohs hardness rating of 9 (second only to diamond at 10), sapphire crystal offers unparalleled scratch resistance. Virtually nothing in daily environments can mar its surface except diamond. This exceptional durability makes it the standard for luxury watches, ensuring decades of crystal clarity.

Sapphire also boasts superior optical properties, featuring high light transmission and low reflectivity. These characteristics enhance dial legibility even under bright lighting conditions, while the material's inherent strength provides maximum protection for delicate watch mechanisms.

When selecting a watch crystal, consider these factors:

• Budget-conscious buyers: Hardened mineral glass offers excellent value, providing sufficient scratch resistance for regular use at a fraction of sapphire's cost.
• Premium durability seekers: Sapphire crystal remains the undisputed choice for long-term scratch resistance and optical clarity, justifying its higher price point.
• Active lifestyles: Those frequently engaging in outdoor activities or manual work benefit most from sapphire's superior damage resistance.

Both materials represent excellent choices for watch crystals. Understanding their respective properties enables informed decisions, ensuring your timepiece remains as visually pristine as its mechanical precision demands.