Blue/ Green/ Pink/ Red/ White Sapphire single crystal watch glass case/ Sapphire optical glass for watch lens
Sapphire Glass
Sapphire optical windows are ideal for applications where high pressure, vacuum, or corrosive atmospheres are a consideration. Sapphire, a single crystal form of Al2O3, is resistant to attack by strong acids due to its high dielectric constant. It has high compressive strength and a high melting point. It is also resistant to UV radiation darkening. Our sapphire optical windows are not coated, but a single layer coating of MgF2 on each surface of the window increases the single surface transmittance to 99% throughout the entire visible spectral region. Please note the SAW series sapphire windows are provided in random axis orientation by default and its birefringent nature could affect the polarization state of your application.
| Diameter: | 30-50mm or customized |
| Thickness: | 3.75mm |
| N.W.: | 8.5g |
| Vickers hardness: | HV2000-2500 |
| Mohs hardness: | 9 mohs |
| High Crystal Purity: | > 99.995% |
| Compressive strength: | 21000kg /cm² |
| Crystal texture: | Hexagonal lattice structure |
| Specific heat: | (20~350ºC)0.181cal/g°C(25ºC) |
| Thermal conductivity: | (20°C) 0.09calc.cm.ºC(25ºC) |
Sapphire Glass for watch case
1. Ultimate Scratch Resistance
With a Mohs hardness of 9, sapphire is second only to diamond. It resists scratches from keys, sand, and other daily objects, keeping the watch surface pristine over time.
2. Crystal-Clear Transparency
Sapphire offers exceptional optical clarity, ensuring the watch dial remains highly visible and easy to read from all angles, enhancing both aesthetics and user experience.
3. Luxurious Appearance
Featuring a smooth, glossy surface and gemstone-like brilliance, sapphire glass adds a premium, sophisticated touch — a preferred material for luxury timepieces.
4. Anti-Aging & UV Resistance
Unlike plastic or ordinary glass, sapphire glass does not yellow or degrade over time, maintaining its clear appearance for years.
5. High Durability for Daily Wear
Sapphire is highly resistant to pressure and impact, making it ideal for everyday use, travel, and sports — minimizing the risk of cracking or breaking.
6. Customizable for Unique Designs
Available in various colors (blue, pink, green, etc.), thicknesses, and surface styles (flat, domed, coated), sapphire glass can be tailored to meet diverse brand design requirements.
Sapphire watch case
Process Step
Sapphire body Sapphire rough shape Sapphire CNC engraving and milling
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Sapphire watch case's material
Our sapphire watch case material is crafted from high-purity single-crystal Al₂O₃, offering exceptional scratch resistance, optical clarity, and long-lasting durability. It is available in a wide range of vibrant colors—including clear, blue, pink, red, green, and white—achieved through uniform doping during crystal growth, not surface coating.
Each piece is 100% bubble-free, inclusion-free, and defect-free, ensuring flawless transparency and consistent light transmission. Advanced processing eliminates internal stress, making the material optically pure and structurally stable.
This sapphire material combines beauty and performance, with excellent resistance to scratches, UV light, and thermal stress. It is ideal for luxury mechanical watches, smartwatches, and sports models.
We support OEM customization in color, thickness, shape, and engraving. Choose our sapphire crystal for a premium, reliable, and visually stunning watch case solution.
Company information
We specialize in the design and volume manufacturing of high performance optical components such as lens,prisms, windows,filters,mirrors and more for use in optical instruments and laser systems, as well as for military, telecommunications,medical, environment monitoring industry,material is widely ranged from optical glass to IR and UV glass.
As a Fast-growing supplier in Optics, we offer excellent service and good quality items,our products have been appreciated by many European and American customers,of course we build a long-term cooperation. zmkj has quickly established itself as a leader in optical components from its advanced technology and quality control.
Sapphire Watch case Q&A
Q1: What makes sapphire glass better than regular watch glass or plastic?
A1: Sapphire glass has a Mohs hardness of 9, making it nearly as hard as diamond. It is extremely scratch-resistant, does not yellow over time, and offers excellent optical clarity, making it far more durable and premium than regular mineral glass or plastic.
Q2: Are your sapphire watch cases really made from 100% sapphire crystal?
A2: Yes. Our sapphire watch cases are made from high-purity, single-crystal Al₂O₃ (aluminum oxide), grown through a precision crystal growth process. Each unit is free of bubbles, inclusions, and surface flaws, ensuring both visual beauty and mechanical strength.
Q4: What sizes and shapes are available for the sapphire glass?
A4: Standard diameters range from 30–50 mm with a thickness of around 3.75 mm. However, we support OEM customization, including shape (flat/domed), edge profile, color, and even engraved designs based on your technical drawings.
