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What is Sapphire Glass?

Customized sapphire glass

Sapphire glass, an exquisite and durable material, has emerged as a gem in the world of high-performance displays and beyond.

At its core, sapphire glass is a synthetic material, engineered from crystalline aluminum oxide, also known as corundum. It shares its composition with the gemstone sapphire, which is celebrated for its deep, lustrous blue color.

What sets sapphire glass apart is its remarkable hardness, surpassing even that of traditional glass. So, in this article, we’ll tell you everything you need to know about sapphire glass, so you don’t have to be lost in learning all about it!

What is Sapphire Glass?


Figure 1: An Image of What Real Sapphire Glass or Sapphire Crystal Looks Like

Sapphire glass is a synthetic, transparent substance formed of crystalline aluminum oxide (Al2O3) that is well-known for its toughness, scratch resistance, and optical purity.

Its toughness and scratch resistance make it popular in premium timepieces, cellphones, camera lenses, and aerospace applications!

Is Sapphire Glass Really a Type of “Glass?”


Figure 2: A Round Sapphire Glass Crystal Made From Aluminum Oxide and Uncrystallized Sapphire

While marketed as “glass,” it isn’t really a type of glass. Instead, it is a material made from aluminum oxide crystallization, specifically at highly-fluctuating temperatures–temperatures that standard glass wouldn’t be able to handle.

Check this video out discussing the differences between mineral and sapphire glasses.

Is Sapphire Glass Real Sapphire?


Figure 3: An Excellent Representation of Sapphire Glass

The sapphire glass that we know of today is synthetic sapphire glass. Contrary to popular belief, it isn’t the “sapphire” we all are thinking of. It’s a rigid, hard, and durable material that’s been smelted and manufactured at high temperatures.

Therefore, sapphire glass is neither a type of glass nor real sapphire.

How Do You Identify Sapphire Glass?

Check this quick 1-minute video out as it details the different tests you can do in identifying sapphire crystals.

Checking whether your material is made from sapphire glass or other material is not as difficult as you think. As a matter of fact, there are a few methods and processes you can do to identify whether what you have is sapphire glass or not, but the most popular is the water dab method.

The Water Dab Method

To do the water dab method, all you have to do is to dab a drop of water onto the surface of your sapphire glass. Then, take note of its behavior – of the water droplet spreads and flows towards the edge of the glass, it is mineral glass. If the drop remains spherical, however, it’s sapphire glass.

Is Sapphire Glass Natural?

No, it’s not. One of the most common misconceptions about sapphire glass is that it’s natural. When, in reality, it’s not. The term sapphire glass simply refers to synthetic sapphire, which is made from the crystallization of pure aluminum oxide at exceedingly high and fluctuating temperatures.

It has the same hardness as the sapphire gemstones without the colored hues.

What is Sapphire Glass Made Of?


Figure 4: Aluminum Oxide, an Ingredient in Making or Producing Sapphire Crystals

Just because it’s called and deemed as sapphire glass, doesn’t mean that it’s entirely made of sapphire. Sapphire glass is this crystalline, technical, and transparent ceramic made from pure aluminum oxide. Because of its overall purity and lackluster of contamination, you’ll notice all sapphire glass units are transparent and colorless.

Hesalite Glass vs. Mineral Glass vs. Sapphire Glass


Figure 5: The Main Differences Between Acrylic, Mineral, and Sapphire Glass

Hesalite, mineral, and sapphire glass are among the few but most-commonly used types of glass in watches and other surfaces. But why are they frequently compared? What makes them special and unique from one another?

Hesalite Glass

The term “hesalite” was first coined by Omega, but, in reality, it’s simply plastic. A few of its other names are plexiglass, acrylic, crylux, etc.

Its primary characteristic is that it’s soft and flexible, which makes it an excellent choice for watches because they won’t shatter. In addition, it’s also impact-resistant, which tears but never splinter. In watches, hesalite glass also appears clearer, cleaner, and more distinct.

However, due to its softness, it’s more sensitive to scratches than harder and more durable materials.

Mineral Glass

On the outside, mineral glass isn’t that fairly noticeable to be different than its two contenders. But, there are quite a few functional and mechanical differences between them and your typical hesalite glass.

Taking from the chemical sense, mineral glass is less likely to experience shatter than hesalite glass. Like the aforementioned glass type, it also has good levels of clarity with minimal reflection distortion. It’s more durable and scratch-resistant than hesalite, and is excellent for applications like sports, eyeglasses, watches, and other similar materials.

Its primary drawback is the moderate impact-resistance. While resistance to scratch and impact is virtually similar with hesalite, it’s predominantly stronger and more durable than plastic, and therefore, more used in the watch industry.

Sapphire Glass

Last, but most definitely not least is sapphire glass. Sapphire glass has been known in the industry as the most exemplary, the clearest, the best, the strongest, and most durable material of all. It takes pride in

its property of being the most resistant to impact and scratches, as well as being the hardest and least likely to break are among the many reasons why watchmakers consider it their go-to material. It’s an excellent material under extremities!

However, that doesn’t mean that sapphire glass is already unbeatable. It has a few quantifiable disadvantages and drawbacks like how it has a strong refraction of light, limiting clarity and readability.

Nevertheless, it’s what many consider as the best type of glass for timepieces and other similar applications.

Comparison Table of Sapphire, Mineral, and Hesalite Glass

For you to understand it better, here’s a table that outlines and gives you the bigger picture of the comparison of these three materials:

Characteristic/PropertyHesalite GlassMineral GlassSapphire Glass
Hardness and Toughness (Mohs Scale)~3~5 to ~69
CompositionPlastic or AcrylicSilicate Minerals (Silica)Synthetic Sapphire Material
Impact ResistanceLowModerateHigh
Scratch ResistanceLowModerateExtremely High
ClarityGoodGoodExcellent Scratch Resistance
DurabilityScratch-ProneDurable EnoughExtremely Durable
Pricing and CostAffordable and CheapMid-Range PricingExpensive and Costly
MaintenanceRequires PolishingMid-Tier Resistance to ScratchesVirtually Maintenance-Free

NOTE: Please keep in mind that the intended traits and properties of these materials vary depending on the treatment they receive.

  • Hesalite glass is known for its use in vintage and space-exploration, and futuristic watches due to its unique qualities and features.
  • Mineral glass is a common choice for many everyday watches and eyeglasses. It can be scratched but easily replaceable.
  • Sapphire glass is the top and best choice for luxury and high-end watches and smartphones, prized for its exceptional durability and clarity.

Sapphire Glass Price: What is Sapphire Glass Worth?


Figure 6: Check Out the Intricacy and Detail Required in Handling Sapphire Glass

When it comes to pricing, a lot of people think of sapphire glass to be an ultra-expensive piece of material. But, that’s not what the case is!

As a matter of fact, there are other similar materials that are exponentially costlier and more expensive than sapphire glass–without bearing its overly-beneficial properties!

One of the key things that separate sapphire glass from other types of glass is its pricing. It’s substantially costlier, but not as expensive as many people think. When you take a look at sapphire glass in Made-In-China, you’ll notice that it costs anywhere between $1 to $10 per piece, depending on several factors, including:

  • Type: Shape, use, or intended application
  • Transmittance: The amount of light it transmits
  • Warranty service
  • Thickness
  • Properties and features

NOTE: The $1 to $10 per-piece cost is actually for wholesale, with minimum requirements of 100 square meters, 100 pieces, etc. So, do your research and try to find shops that don’t require as much!

Made-In-China documented the average prices of sapphire glass units from various within the country!

How is Sapphire Glass Made?

The process or method of making or manufacturing sapphire glass is neither different nor far from how traditional mineral or soda-lime glass is made. Others say that it’s made from excruciatingly highly-fluctuating temperatures, while others say that it can be made in regular, standard warm environments.

Nevertheless, here’s the simple and most common way of how sapphire glass is manufactured:

  1. The first step is the collection of the sapphire crystals. They’re first manufactured and created in varying shapes and sizes.
  2. Then, using chemicals like aluminum oxide, they’re heated and combined with uncrystallized sapphire. It’s usually done within crucibles in order to maintain and capture heat efficiently and effectively.
  3. Uncrystallized sapphire pieces and bits are added into the mixture within the crucible, which then undergoes extreme heating.
  4. After it melts, it’s cooled down until it reaches the required properties.
  5. When it’s cooled down, it’s cut and shaped according to the desired physical attributes.
  6. Lastly, they’re processed, finished, and polished, whatever the requirement of the client.

NOTE: This is just a general representation of how sapphire glass pieces and units are made. Just because this process is outlined this way, doesn’t mean that it’s followed by all manufacturers and suppliers.

How Strong is Sapphire Glass?

Sapphire glass is known as one of the strongest, most durable, and most rigid types of materials, having a hardness of 2,000 HV and grade 9 in the Mohs scale, you can already expect how tough, hard, and durable it can be.

In regular terminology, sapphire glass is not easily scratched. In fact, only a few materials are able to scratch it, real diamonds, which have HV ratings of 4,500 to 10,000 being a part of it. Here’s a quick video from SeriousWatches, differentiating mineral and sapphire glass in terms of breakage and damage.

Pros and Cons of Sapphire Glass


Figure 7: Here Are Four Different Sizes of Round Sapphire Glass Crystals

Just because they’re known and renowned as one of the best, strongest, and most commonly-used types of glass in various industries, it still has benefits and drawbacks. This doesn’t mean that they’re perfect.

Let’s take a look at some of the advantages and pros of sapphire glass first.

Here’s Unauthorized Dealer’s quick video discussing the pros and cons of having a sapphire glass on a watch!

Pros of Sapphire Glass

Here are some of the advantages and pros that sapphire glass offers, giving the reasons why they’re chosen to be used in different industries:

Extraordinary Hardness

It has a Mohs hardness of 9 and is regarded the third hardest mineral after diamond with an external hardness of 10 and moissanite with a hardness of 9.5. It is inherently tougher than glass and has a stronger scratch resistance unless it comes into touch with materials of comparable or greater hardness. It also possesses a total tensile strength of 2000 mega Pascals, making it ten times more durable than stainless steel.

Brute Strength

Besides its hardness, it’s also revered as one of the strongest and most resilient synthetic materials in the world. The strength comes from its scratch and impact-resistance, as well as the hardness that it holds.

Thermal Shock Resistance

Because of its superior electrical insulating characteristics or electrical resistance, it is appropriate for use as an insulating substrate in electronic components. Furthermore, while being an insulator, it has comparable heat conductivity as stainless steel. This material has a good thermal shock resistance and a melting temperature of 2030 degrees Celsius.

High Melting Point

Following that, sapphire glass is also known to have extremely high melting points, typically higher and more extreme than regular or traditional glass. It has a melting point of up to 2,000 °C, versus mineral glass’s 1,550 °C and 1,600 °C, making it suitable for high-temperature applications.

Cons of Sapphire Glass

Now, let’s move onto discussing the cons and drawbacks of sapphire glass.

High Light Refraction

Sapphire glass has a high refraction rate, meaning, the reflections aren’t 100% clear, limiting visibility of whatever’s behind it. In watches, it’s often one of the things that are complained about.

Unremovable Scratches

Because of their hardness, when scratched, it’s often unremovable. This is no magic trick, it’s just because of the level of hardness and durability that it has, making dents and scratches unrecoverable after some time.

Production/Costly Manufacturing

Last but most definitely not least is production. It’s difficult to produce in large amounts, and if you’ll do so, it will be extremely expensive. This is one of the things where mineral glass is actually better.

Can You Scratch Sapphire Glass?

Yes, it can be scratched by a few materials like real earth-harvested diamonds, which have hardness levels that are 10 Mohs or about 10,000 HV.

What Are the Applications of Sapphire Glass?

Sapphire glass has a ton of applications and uses, and among the most common would be in the following fields and industries:

  • Watches, Jewelry, and Luxury Items
  • Electrical Components
  • Oil, Gas, and Energy Sectors
  • Medical and Pharmaceutical Industries
  • Glass Alternatives
  • Lightnings and Lasers
  • Optics
  • Advanced Technology
  • And Many More

Characteristics, Properties, and Traits of Sapphire Glass

Sapphire glass is known to have a wide array of traits and characteristics. Here’s a table that discusses the different properties and traits of sapphire glass that you should know about:

PropertyUnits of MeasurementValue
Compressive StrengthMPa2,000
Densityg/cm33.98
Flexural StrengthMPa480 to 900
Young’s ModulusGPa350
Thermal ConductivityW/m.K40
Maximum Operating Temperature°C1,800
Melting Temperature°C2,000+

Where Can You Get High-Quality Sapphire Glass?

If you’re on the hunt for some of the world’s best, highest-quality, but reliable sapphire glass units, GLASHern can be of assistance to you.

We’ve been renowned as one of China’s leading glass manufacturers of all time! From Gorilla Glass, Quartz glass, Borosilicate Glass, to custom camera lenses, UV transmitting glasses, and many more – you can definitely bank and count on us!

Our 14-year experience in glass raw material production have been sought out by organizations and companies worldwide! We’re also an unrelenting force when it comes to precision glass and decorative glass products, too.

  • We use state-of-the-art glassmaking processes and materials since 2009
  • GLASHern boasts of a total of 9 certifications in different regions and qualities
  • Over 200 production equipment available
  • We export to over 50 countries
  • We’re equipped with a team of highly-skilled engineers and glassmaking experts

Get world-class quality service partnered with top-tier products with GLASHern! Never worry about where you’ll get your sapphire glass units next because we’ll be here ready to assist you!

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