Sapphire: The Clear Choice for Military Applications and Beyond

In case you missed it, something BIG is happening in the sapphire industry.

But just what are the practical applications for a massive slab of sapphire?


First and foremost, sapphire is hard, and as a result, extremely durable. On a scale of hardness — the Mohs scale to be exact — sapphire is the second hardest naturally occurring material, next only to diamond.

Sapphire Infographic

This makes sapphire a clear choice over glass for use in harsh environments, such as deserts. Sapphire is harder than quartz (the main component of sand), and does not scratch as easily as glass would, making it ideal for a variety of applications that come in contact with sand. One that comes to mind is the lens of a military-issue scope. Currently, the military is beginning to swap out scopes that have lenses made of glass that scratch easily, in favor of sapphire lenses.

Besides being useful as a lens, sapphire is so hard it can be used as transparent armor — hard enough that it can even shatter a .50 caliber bullet if thick enough. This leaves endless possibilities for its use in tank windows, transport vehicles, etc.


Sapphire can withstand extreme temperatures without losing its integrity, making it ideal for space exploration. Some regions of space get less than I degree C above absolute zero.  On the other hand, during re-entry, NASA says the external surfaces of spacecraft can reach a temperature in excess of 1,500 degrees Celsius. With its ability to withstand extreme high and low temperatures, sapphire is an ideal material for use in the cones of spacecraft.

Along with the ability to withstand extreme temperatures, sapphire is also known for being “radiation hard,” meaning that sapphire does not break down when exposed to radiation. Once astronauts leave the protection of earth’s magnetic field and atmosphere, radiation becomes a concern. Most materials rapidly change chemical properties under radiation exposure, but because sapphire is less susceptible, it is well suited for space exploration.


Oil and Gas

Nasty chemicals and harsh sea air take a toll on glass and metals, but sapphire is chemical-resistant. In the oil and gas industry, harsh chemicals are omnipresent, so tools and machinery need to be able to withstand the effects of exposure. Thanks to its corrosion resistance, sapphire is a perfect material for use in the oil and gas industry, specifically in the harsh remote areas where oil and gas exploration takes place.

Sky's the Limit

For sapphire, the sky’s the limit when it comes to future uses. Whether it is in spacecraft or oil and gas exploration, new manufacturing methods are ensuring that sapphire will be an important material for years to come.

New Applications for Sapphire: Aerospace & Defense, Part 1 of 3

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Range of sapphire products available from Rubicon Technology including large optical windows and other shapes for aerospace and defense.

Sapphire’s unique properties make it a perfect material for high-performance applications due to its optical transparency, physical strength, resistance to abrasion and corrosion, temperature durability, chemical inertness, and bio-compatibility. As a result, it is perfectly suited for extreme environments where material durability is just as important as optical clarity.

One extreme use case is in the aerospace and defense industry where there’s a need for rugged windows for targeting pods and missile domes, most notably for the US F-35 fighter jet, that may come in contact with harsh conditions from the harsh, gritty desert with extremely high temperatures to high altitudes with extreme low temperatures.

Market research firm Yole Developpement determined that non-substrate applications for sapphire in the defense, semiconductor and other applications represent 25% of the sapphire industry revenue in a new study.  The market represents a solid growth opportunity for sapphire makers.

While there is opportunity, innovation is needed.  Sapphire traditionally has been limited to smaller shapes and sizes using traditional growth methods.  As sensor technology and applications, in defense and aerospace in particular, have evolved, the size requirements for sapphire windows have grown substantially.  One company that is innovating sapphire crystal growth is Rubicon Technology.

In a recent paper, Rubicon’s Dr. Jonathan Levine, Director of Technical Business Development, detailed how Rubicon successfully produced very large sapphire blanks using a highly modified horizontal directional solidification process. This new method, named the Large‐Area Netshape Crystal Extraction (LANCE) system is currently able to produce crystals of several different orientations. The company plans to produce sapphire windows as large as 36 x 18 x 0.8 inches.

For Further Reading Blog, Opportunities for Sapphire: New Applications & Markets Explained, Blog, How Large Can You Go? Sapphire Windows Grow Up and Across,

Rubicon Technology, Synthesis and characterization of large optical-grade sapphire windows produced from a horizontal growth process,