Almost as hard as diamond
Sapphire glass is a very expensive raw material and is only made to order. We need excact specification of the glass to make an order. It cannot be processed afterwards.
In addition, extra delivery time must be expected. In return, you can choose the thickness of the glass yourself.
At present, we can supply sapphire crystal sheets up to Ø250 mm.
As the glass is costly, many customers choose for example to use chemically tempered glass instead.
Contact us today to get more information
QUICK FACTS ON SAPPHIRE GLASS
- High transmission properties
- Hard to scratch
- Withstands high temperatures
- Typically used for sight glass, special cameras, barcode scanners and for very exclusive watches
- Fast delivery on sapphire crystal sheets up to Ø250 mm
Properties of the sapphire crystal
Sapphire glass is an optically clear crystal. Due to the cost of the glass it is not widely used. When some customers demand sapphire glass, it is mainly because of its hardness. The glass is very hard and ranks second on the Mohs scale of mineral hardness – right after diamond (sapphire is a variety of corundum). The glass is very strong and very difficult to scratch.
In addition, sapphire crystal is chemically resistant to common acids and bases – even at temperatures up to 1000 °C. The glass has a high purity and a very wide optical transmission of + 85% in the whole range from UV to IR (200-4000 nm).
The excellent properties of the glass make it a coveted type of glass. But as the properties comes with a cost, other glas types like quartz glass or chemically tempered glass are often used as an alternative solution.
Sapphire Glass – Extended Knowledge, Properties and Applications
Sapphire glass (single-crystal aluminium oxide, Al₂O₃) is one of the most advanced and durable materials used in technical and industrial applications. On the existing landing page, sapphire is already described as extremely hard, scratch-resistant and durable. Below, these qualities are explored in greater depth to provide a clearer understanding of why sapphire is, in many applications, the only realistic choice.
Crystal structure and purity
Sapphire glass consists almost exclusively of aluminium oxide with an exceptionally high degree of purity. The material is grown as a single crystal, resulting in a completely uniform structure without internal stresses or impurities. This purity is crucial for both mechanical strength and optical performance.
The crystal structure is hexagonal, and sapphire can be manufactured in different orientations depending on whether the focus is optical clarity, electrical properties or mechanical stability. The C-plane is particularly used in optical applications, as it reduces crystal-related light distortion.
Extreme thermal stability
Sapphire is distinguished by its ability to withstand very high temperatures without deforming or losing strength. The material has a melting point above 2,000 °C and can be used without issue in environments where conventional glass and quartz glass would begin to degrade.
Its low thermal expansion ensures that sapphire maintains dimensional stability even when subjected to repeated thermal shock. In practice, this makes sapphire ideal for furnace windows, high-temperature sensors, laser applications and technical equipment where heat and precision must coexist.
Outstanding mechanical strength
Sapphire is one of the most wear-resistant materials available. With a hardness surpassed only by diamond and exceptionally high compressive strength, sapphire can withstand mechanical impacts, particle abrasion and long-term wear without damage.
The material is virtually scratch-proof and retains its smoothness and optical clarity even when exposed to sand, salt, high-pressure environments and continuous mechanical friction. As a result, sapphire is commonly used in industrial inspection windows, underwater cameras, precision instruments, watches, sensors and robotics.
Optical clarity across a wide spectrum
Sapphire is naturally colourless and exhibits very high transmission in ultraviolet, visible and infrared light. This makes the material particularly valuable in optical applications where multiple wavelengths must pass unobstructed through the same window or lens.
The combination of optical quality and scratch resistance makes sapphire a preferred material for cameras, measurement systems, medical instruments, laser optics and advanced sensors.
Chemically resistant – even at high temperatures
Another key characteristic of sapphire is its chemical resistance. The material does not react with acids, bases, solvents, saltwater or organic substances, even at very high temperatures.
Where other materials gradually degrade in chemically aggressive environments, sapphire maintains both clarity and strength. This makes it well suited for process equipment, marine installations, laboratory instruments, the oil and gas industry, and environments with high humidity, salt or corrosion.
Applications in modern industry
Sapphire glass is used across a wide range of technical environments, from controlled conditions to extreme settings:
Optics and sensor technology
- Camera and sensor cover glass
- IR- and UV-transmitting windows
- Laser optics
- Optical lenses, domes and protective windows
High-temperature equipment
- Furnace windows
- Viewing panels in industrial furnaces
- Combustion and process systems
- Equipment exposed to high thermal loads
Extreme environments
- Submersible vehicles
- Drones and missile systems
- Offshore equipment and marine sensors
- Inspection systems in sand- and dust-filled environments
Medical technology
- Sterilisable components
- X-ray and MRI-compatible windows
- Laser-based surgery and dermatology
Electronics and semiconductors
- Substrates for LED production
- High-frequency components
- Microelectronic chips and sensors
Why sapphire often replaces glass and quartz glass
For many years, tempered glass, borosilicate glass and quartz glass have been standard materials in technical installations. However, as demands for precision, durability and extreme resistance increase, more industries are choosing sapphire as their primary material. The most common reasons include:
Long service life
Sapphire lasts for decades in environments where glass would quickly develop micro-damage, scratches or lose clarity.
No deformation at high temperatures
Even under extreme temperature fluctuations, sapphire retains its shape and optical quality.
Combination of strength and optical clarity
It is rare to find a material that is both exceptionally strong and optically clear, while also functioning across UV, visible and IR wavelengths.
Complete chemical stability
Sapphire is largely unaffected by chemicals and corrosive environments—something glass cannot match.
Better operational economics in practice
Although sapphire is more expensive to manufacture, its long service life often results in lower total costs due to fewer replacements and reduced downtime.
Sapphire glass is one of the most advanced and reliable materials available for optical and industrial applications. The combination of extreme hardness, high temperature tolerance, chemical stability and broad optical transmission makes sapphire the natural choice when materials must withstand the most demanding conditions.
