Watch glass is one of the important accessories of the watch case, which can effectively protect the watch dial and the watch hand from being damaged.Among them acrylic glass, sapphire crystal and mineral glass are the most commonly used materials for watch glass.  But in this blog post we focus on mineral vs sapphire crystal.While both materials have their own benefits, it is important to understand the differences between the mineral crystal vs sapphire so you can make an informed decision when purchasing a watch. Simply put Sapphire is more scratch-resistant than Mineral glass and is more resistant to cracking.

  We will explore the properties and benefits of crystal sapphire and mineral glass watch, and compare their differences in terms of durability, scratch resistance, clarity, and cost,how to distinguish sapphire glass from mineral glass, etc.

mineral vs sapphire crystal

Table of Contents

Sapphire crystal

  Sapphire crystal is an artificially created material that is produced by crystallizing pure aluminum oxide at extremely high temperatures. Its physical properties are similar to those of natural sapphires, including exceptional hardness that is second only to diamonds on the Mohs hardness scale. The synthetic sapphire shares the same level of hardness as natural sapphires, making it highly resistant to scratches and damage.Because of its extreme hardness, the glass of dive watches is sapphire crystal.

what is mineral glass

Mineral glass

   Mineral glass is a material made of glass and is common on most mid-range watches.They are slightly more expensive than plastic or acrylic crystals, but significantly better scratch resistance. Now almost all mineral glass watches are tempered mineral glass.Mineral glass, on the other hand, can be heat-treated or coated to increase its hardness and make it less susceptible to scratches.

    The raw materials of mineral crystal are mainly silica and sodium carbonate.  Watch mineral glass is also known for its clarity and transparency, making it an ideal choice for watches.

Mineral crystal vs Sapphire

Scratch resistance

Sapphire Crystal has a hardness of 9, making it the hardest of all watch glass materials.It usually requires a diamond or similar substance to scratch it.  In comparison, Mineral Glass has a hardness between 5 and 7, making it more prone to scratches. Once the glass is a lot scratched or broken, you can choose to send it to a professional watch repair store to polish or replace the glass.

This is why many dive watches are made with crystal sapphire glass.


Sapphire Crystal has higher transparency than other watch glass materials due to its high crystalline quality, and it doesn’t become hazy over time and under environmental stress.  Mineral Glass has a relatively high transparency, but it’s slightly inferior to Sapphire Crystal.Therefore, in some dark environments such as in diving and other activities, to clearly see the time displayed, a diving watch with sapphire glass is the best choice.


Due to its high cost and relatively fragile nature, Sapphire Crystal is usually limited to high-end watches.  If the watch is subjected to impact or shock, it may cause the glass to shatter or crack,which is also a disadvantage of sapphire glass. In comparison,mineral glass is relatively durable but relatively impact resistant.


Sapphire Crystal is typically more expensive than Mineral Glass and is a high-end watch glass material.  In contrast, Mineral Glass is commonly used in low- to mid-range watches and has a lower cost. The cost difference between Sapphire crystal and mineral glass is significant. Generally, Sapphire crystal surface glass of the same size and thickness can cost 5 times or more than mineral glass.

It’s important to note that the performance of watch glass materials is not only determined by the material itself but also influenced by its manufacturing process and application.For example, due to the high hardness of sapphire crsystal, the processing of sapphire glass requires grinding tools with diamonds.

Mineral glass VS sapphire crystal?Hard to decide,Sapphire coated mineral glass is also a good solution.

    Sapphire coated mineral glass refers to a type of glass surface that is made of mineral glass but has been coated with a layer of sapphire crystal for increased scratch resistance and durability.

    This innovative material boasts improved impact resistance compared to traditional mineral glass, while its sapphire coating ensures that only a diamond can scratch its surface. As a result, the combination of mineral crystal glass with a thin sapphire layer provides a substantial increase in both impact resistance and scratch resistance, making sapphire coated mineral glass a compelling option for various applications.

Conclusion-Mineral crystal vs sapphire crystal

      In summary, sapphire crystal and mineral glass both have their own benefits and drawbacks. Sapphire crystals withstand scratches very well and can only be scratched with certain rare materials, mainly diamonds, especially hard rock types.  Mineral glass, which is commonly used to make watch glasses, is easier to scratch but better able to withstand impact.  While sapphire crystal is more durable, scratch-resistant, and transparent, mineral glass is more affordable and still offers a high level of durability and scratch resistance.  When choosing between the mineral vs sapphire crystal, it is important to consider your budget, intended use, and aesthetic preferences.As a professional watch supplier, we can provide different grades of sapphire glass and mineral glass for customers to choose.


How To Tell Sapphire crystal From Mineral glass

Water drop

 By the way, you can easily check whether your favorite watch comes with sapphire glass using the so-called water drop method: dab a drop of water on the surface of the watch glass and observe its behavior.  If the drop remains spherical, it is sapphire crystal.  If it spreads and flows, it is mineral glass.

How to tell mineral glass from sapphire crystal
The difference of Sapphire crystal and mineral glass

 The glass color

Crystal Sapphire and mineral glass can be distinguished by the color of the side of the glass. If the color is milky white, it’s sapphire crystal glass. If it’s blue, it’s mineral glass.

Use a tool near you, similar to a knife to scratch the glass

  If the knife scratch the glass, it’s mineral glass. If glass can’t be scratched, it’s crystal sapphire glass.

Touch and fee

  If you touch sapphire, you will feel cold, it is not mineral.

Related products-Sapphire crystal watch

   Sapphire crystal watches are highly recommended for anyone looking for a timepiece with exceptional durability and scratch resistance. Sapphire crystal is second only to diamonds in terms of hardness, making it an ideal material for watch faces that are exposed to daily wear and tear. In addition to its toughness, sapphire crystal is also highly transparent and clear, providing a crystal-clear view of the watch hands and diala sapphire crystal watch is an excellent choice. So why not treat yourself to the unparalleled beauty and durability of a sapphire crystal watch today?

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