Sapphire Glass: Advantages and Disadvantages

Sapphire Glass: Advantages and Disadvantages

Sapphire glass is an application of synthetic sapphire generally produced by subjecting aluminum oxide powder under extreme heat and pressure. Further heat treatment removes internal stresses before processing into thin sheets. The resulting output is a transparent material that is more durable than standard glass. Take note that a synthetic sapphire has the same physical properties as naturally-occurring sapphire.

The extraordinary durability of sapphire glass makes it ideal for consumer electronic devices that use digital output displays such as smartphones and tablet computers. In fact, Apple initially planned to equip the in-plane switching LCDs of iPhone 5S, iPhone 6, and iPad Mini 3 with sapphire glass screens. However, these products came with Gorilla Glass screens instead.

Advantages of Sapphire Glass: Applications and Benefits

Although sapphires are blue in color, a sapphire glass is highly transparent to wavelengths of light between 150 nanometers and 5500 nanometers. This range gives the material a very wide optical transmission band from ultraviolet to near-infrared.

It is worth mentioning that the human eye can only discern wavelengths between 380 nanometers and 750 nanometers. In other words, a sapphire glass passes the most basic requirement of an ideal screen: light should pass through it, and an individual should clearly see through it.

But the real advantage of sapphire glass lies in its extraordinary hardness. The material is nearly twice as hard as standard glass, and it is almost as hard as a diamond. For a quick reference, the sapphire has a value of 9, while a diamond has a value of 10 under the Mohs scale of mineral hardness. This means that sapphire glass is almost resistant to scratch unless it will come in direct and hard abrasive contact with a diamond.

Sapphire glass is not only hard but also strong. Because it shares similar properties with naturally-occurring sapphire, it has a compressive strength of 2000 mega Pascals. This makes the material about 10 times stronger than stainless steel.

Resistance to thermal shock is another advantage of sapphire glass. Sapphire has an extremely high melting point of 2030 degrees Celsius.

Just imagine having consumer electronic devices equipped with a sapphire glass screen. These devices would undoubtedly have longer lifespans. Consumers can use their smartphones or tablet computers without worrying too much about unexpected scratches and bumps.

Disadvantages of Sapphire Glass: Drawbacks and Limitations

Despite the aforementioned advantages of sapphire glass, it has several disadvantages that make it impractical for use in consumer electronic devices. An interview with material scientists Richard Lehman and Dr. Helen Chan by Tim Bajarin of Time magazine highlighted these drawbacks.

For starters, despite an established manufacturing process, it is difficult to produce in large quantities. Lehman said that a standard glass costs a nickel per square inch to manufacture, while a sapphire glass costs several dollars per square inch. The production cost would drive the prices of associated products such as laptops or smartphones.

There are also environmental issues associated with its production. Dr. Chan noted that it would take more than 2030  degrees Celsius to melt sapphire. This would consume a tremendous amount of energy resulting in high energy costs. Undeniably, mass-produced sapphire glasses would have a higher carbon footprint than standard glass technologies.

Note that consumer electronic devices, such as smartphones and tablets, have short lifespans. Users would purchase these devices and keep them for about one to two years before replacing them with newer models. Manufacturers are also introducing newer editions or generations of smartphones and tablets every year.

The market for smartphones and tablets has become highly competitive—leaning towards yearly innovations and iterations. Equipping these devices with an expensive material could be impractical for most consumers. From the perspective of manufacturers, they would end up choosing between the two: either keep the price low while upgrading pertinent hardware specifications and maintaining form factor standards or keep the price high due to advanced hardware specifications and a more durable form factor.

Another disadvantage of sapphire glass is durability. It is still susceptible to cracking and shattering despite having high resistance against scratches. The durability of glasses and other glass-like materials sits on a scale: harder materials are more scratch-resistant but are less resilient against cracks, while softer materials are more crack-resilient but less scratch-resistant. Harder materials are fundamentally more brittle than softer ones.

Conclusion: Current and Future Applications

The advantages of sapphire glass make it an ideal screen material for consumer electronic devices. Consumers are looking for devices that could stand day-to-day use amid unexpected overuse.

However, because of the disadvantages mentioned above, it would be impractical to equip smartphones or tablet devices with this material without raising their overall price. Take note also that these devices have a shorter lifespan than other products.

Equipping popular consumer electronic devices with sapphire glass screens would definitely raise their price due to higher manufacturing costs. Will it be worth it? The answer depends on the preference of consumers. It is possible that manufacturers could choose this material for their exclusive luxury smartphones.

Nonetheless, considering the popularity of high-end smartphones from Apple and Samsung, among others, it would be impractical to use sapphire glass screens.

It is therefore not surprising that to this date, sapphire glass materials are popular in products with lengthier lifespans to include glasses or crystals of watches, windows or armored-vehicles, bullet-proof glass, and screens or visors in military body armor suits, among others.

But it is also worth mentioning that this material has been used in several parts of consumer electronic devices and accessories. There are screen protectors for smartphones and tablets made of synthetic sapphire. The glasses found on the cameras of newer generations of iPhones are also made from this material.


  • Bajarin, T. 2015. “Why Sapphire Glass is Not the Future of Smartphones.” Time. Available online
  • Malitson, I. H. 1962. “Refraction and Dispersion of Synthetic Sapphire.” Journal of the Optical Society of America. 52(12): 1377. DOI: 1364/josa.52.001377
  • Sutherland, F. L. 2017. “Sapphire, A Not So Simple Gemstone.” American Mineralogist. 102(7): 1373-1374. DOI: 2138/am-2017-6105