January26 , 2023

    Types Of Watch Crystals: Materials, Styles, and Care

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    When it comes to watches, the crystal is often overlooked. But the truth is, the watch crystal plays a crucial role in protecting the inner workings of your timepiece and determining its overall appearance.

    In this ultimate guide, we will explore the different types of watch crystals, the various styles available, the role of each crystal in protecting your watch, and how to choose the right crystal for your timepiece.

    What is a watch crystal?

    A watch crystal is a transparent covering that protects the watch’s face and allows time to be read. It is made from various materials, including sapphire, mineral, and acrylic, and it comes in different styles, such as domed, flat, and sapphire crystals. 

    The watch crystal is an essential part of any timepiece, as it protects the inner workings of the watch from damage and dust. The crystal forms a barrier between the watch’s face and the outside world, preventing dust, debris, and other contaminants from entering the watch. This is especially important for mechanical watches, as these watches have delicate internal components that can be easily damaged by dirt and debris.

    In-depth Read: The Anatomy of a Watch: A Guide to the Components of a Timepiece

    The Different Types Of Watch Crystals

    Several materials can be used to make watch crystals, each with unique properties and characteristics. The three most common materials are sapphire, mineral, and acrylic.

    Sapphire crystal

    Sapphire crystals are considered the best option for watch crystals due to their unmatched durability and scratch resistance. Sapphire crystals are so hard that they are second only to diamonds on the Mohs scale of mineral hardness. This makes them virtually impervious to scratches and other types of damage, making them an excellent choice for daily wear.

    Sapphire boules grown by Rubicon Technology – photo Matthew Montgomery

    In addition to their durability, sapphire crystals are highly transparent, allowing for excellent legibility and a clear view of the watch’s face. This is especially important for professional users, such as pilots and divers, who rely on their watches to perform critical tasks in challenging lighting conditions. Sapphire crystals also have a high refractive index, which can bend light in interesting ways, creating a wide range of visual effects.

    Sapphire crystals are highly transparent, allowing for excellent legibility and a clear view of the watch’s face.

    However, sapphire crystals also have some disadvantages. The most significant disadvantage is their cost. Sapphire crystals are the most expensive option for watch crystals, making them a luxury choice for many watch enthusiasts. They are also brittle, meaning they can crack or shatter if subjected to too much force. Additionally, sapphire crystals are difficult to work with, requiring specialized tools and techniques to cut, shape, and polish.

    Patek Philippe 5980R – NAUTILUS with Saphire crystal

    Overall, sapphire crystals are an excellent choice for watch crystals due to their unmatched durability and scratch resistance. They are also highly transparent and can create various visual effects. However, their high cost and brittleness make them a luxury choice for many watch enthusiasts. While sapphire crystals may not be the right choice for everyone, they are an excellent option for those who want the ultimate durability and scratch resistance for their timepieces.

    Related reading: PVD Coating: Enhancing the Beauty and Durability of Watches

    Sapphire Crystal Hardness

    The hardness of sapphire crystal is 9.0 on the Mohs scale of mineral hardness, which makes it the second hardest material on earth below diamond, but still harder than most other minerals like quartz (7.0), topaz (8), and Zirconia (8.5).

    Sapphire crystal, second hardest material on earth below diamond on Mohs scale.

    The Mohs scale is an internationally accepted system that measures the ability of one substance to scratch another. It’s based on ten minerals, with talc being the softest (1) and diamond being the hardest (10).

    Can sapphire crystal crack?

    Sapphire crystals are known for their hardness and scratch resistance, but they can still crack or shatter if subjected to too much force. This is because sapphire crystals are brittle, which means that they can break or shatter if they are subjected to a sudden impact or other forms of mechanical stress. 

    This can happen if the watch is dropped or if it is subjected to extreme temperatures or other extreme conditions. However, sapphire crystals are less likely to crack or shatter than other materials, such as mineral glass or acrylic resin, due to their incredible hardness and resistance to damage. Although sapphire crystals can still be scratched by harder materials like diamonds or other gemstones with higher Mohs scales, they are generally considered to be the most durable and scratch-resistant option for watch crystals.

    Take a closer look: What Actually Is Watch Dial? Which One Is Better

    How expensive Is a Sapphire crystal?

    Sapphire crystals are considered to be the most expensive option for watch crystals due to their unmatched durability and scratch resistance. The cost of a sapphire crystal can vary depending on the size and shape of the crystal, as well as the quality of the sapphire itself. 

    However, in general, sapphire crystals are significantly more expensive than other materials, such as mineral glass or acrylic resin. The price of sapphires can vary depending on the market, with some costing $1,000 per carat or more while others sell for over $13,000 apiece. The most expensive sapphire ever sold cost its owner a whopping $135,000 per carat. 

    It’s common for a high-end timepiece to have a sapphire crystal and be priced at over $10,000 due to the difficulty and time-consuming nature of producing sapphire crystals, as well as their unmatched durability and scratch resistance. Overall, while sapphire crystals may be expensive, many people consider them to be a worthwhile investment for their timepieces.

    When was Sapphire Crystal First Used?

    The use of sapphire crystals in watchmaking dates back to the early 20th century. At the time, watchmakers were looking for new materials that could be used for watch crystals, as the existing materials, such as mineral glass and acrylic resin, were not durable enough to withstand the rigors of daily wear. Sapphire crystals, which are made from a type of crystal called corundum, were considered to be a promising material due to their incredible hardness and scratch resistance.

    In one of his blog posts, Benjamin Arthur from Benswatchclub conducted a durability test on various types of watch crystals to see how well each one held up against scratches. He used a series of tools to simulate everyday wear and tear, and then rated each crystal based on how well it resisted scratches. He also included detailed photographs and notes on his findings, making it a valuable resource for anyone looking to learn more about the different types of watch crystals and their durability.

    Crystals scratch test – photo by Benjamin Arthur

    The first use of sapphire crystals in watchmaking is credited to Swiss watchmaker Girard-Perregaux, who used sapphire crystals in their high-end watches in the early 1900s. However, it was not until the 1970s and 1980s that sapphire crystals became widely used in the watchmaking industry, as advances in manufacturing technology made it possible to produce sapphire crystals in large quantities and at a reasonable cost.

    Today, sapphire crystals are considered to be the standard material for watch crystals, due to their unmatched durability and scratch resistance. Most high-end and luxury watches are equipped with sapphire crystals, and many affordable watches also use sapphire crystals due to their durability and affordability. Overall, the use of sapphire crystals in watchmaking has a long history, and they remain the material of choice for many watch enthusiasts and collectors.

    For a fuller understanding: 23 Different Types of Watch Hands: Your Guide to Timekeeping

    Mineral Crystal

    Mineral crystals, also known as mineral glass, are made from a type of glass that has been treated with chemicals to make it harder and more resistant to scratches. While not as hard as sapphire crystals, mineral crystals are still relatively durable and provide good scratch resistance. This makes them a good choice for those who want a balance of durability and affordability in their watch crystals.

    In addition to their durability, mineral crystals are also less expensive than sapphire crystals. This makes them a more affordable option for those on a budget or for those who have multiple watches and want to use different crystals on each one. Mineral crystals are also relatively easy to work with, as they can be cut, shaped, and polished using traditional glass-working techniques.

    However, mineral crystals also have some disadvantages. One of the main disadvantages is that they are less transparent than sapphire crystals. This can make reading time difficult, especially in bright light conditions. Mineral crystals also have a lower refractive index than sapphire crystals, meaning they cannot create the same range of visual effects. Additionally, mineral crystals are more prone to scratching and other types of damage than sapphire crystals, and they are not as scratch-resistant.

    Overall, mineral crystals are a good option for those who want a balance of durability and affordability in their watch crystals. They are less expensive than sapphire crystals and provide good scratch resistance. However, they are less transparent or scratch-resistant than sapphire crystals. There may be better choices for professional users or those who are particularly hard on their watches.

    Acrylic Crystal

    Acrylic crystals, also known as plastic crystals, are made from a type of plastic called acrylic resin. Acrylic crystals are the least expensive option for watch crystals, making them a popular choice for entry-level watches and budget-friendly timepieces. They are also relatively easy to work with, as they can be cut, shaped, and polished using traditional plastic-working techniques.

    One of the main advantages of acrylic crystals is their affordability. Acrylic crystals are significantly less expensive than sapphire or mineral crystals, making them a good option for those on a tight budget. They are also relatively lightweight and flexible, which can make them more comfortable to wear than heavier crystals. Additionally, acrylic crystals are available in a wide range of colors, allowing for a greater level of customization and personalization.

    However, acrylic crystals also have some disadvantages. One of the main disadvantages is their lack of durability and scratch resistance. Acrylic crystals can easily be scratched and damaged, and they are not as scratch-resistant as sapphire or mineral crystals. This can make them a poor choice for professional users or those who are particularly hard on their watches. Additionally, acrylic crystals are not as transparent as sapphire or mineral crystals, which can make it difficult to read the time, especially in bright light conditions.

    Overall, acrylic crystals are a good option for those who are on a tight budget and want an affordable watch crystal. They are also available in a wide range of colors, allowing for greater customization and personalization. However, their lack of durability and scratch resistance make them a less-than-ideal choice for professional users or those who are hard on their watches.

    Sapphire-coated mineral crystal

    Sapphire-coated mineral crystal is a type of watch crystal that combines the durability of sapphire crystals with the affordability of mineral glass. The crystal is made from a layer of sapphire crystal that is coated onto a layer of mineral glass. This provides the watch with the scratch resistance and durability of a sapphire crystal while still being less expensive than a sapphire crystal.

    The main difference between sapphire-coated mineral crystal and regular sapphire crystal is the cost and durability. Sapphire-coated mineral crystal is less expensive than sapphire crystal, as it uses a layer of mineral glass as the base material. This makes it a more affordable option for those who want the durability and scratch resistance of sapphire crystals without the high cost. However, sapphire-coated mineral crystal is not as durable as regular sapphire crystal, as the mineral glass layer can still be scratched or damaged.

    Overall, sapphire-coated mineral crystals are a good option for those who want the durability and scratch resistance of sapphire crystals without the high cost. It provides many of the benefits of sapphire crystals while still being more affordable than a regular sapphire crystal. However, it is not as durable as regular sapphire crystal, and it may not provide the same level of protection for your watch.

    Krysterna Crystal

    Krysterna crystal is a brand name for a line of watch crystals that are made by Stuhrling and its subsidiary Akribos. Krysterna crystals are made from a synthetic sapphire material, which provides the watch with the durability and scratch resistance of a sapphire crystal while still being more affordable than a regular sapphire crystal. This is what they say in their website :

    Our Krysterna crystal, created using the centuries-old Verneuil Process that successfully produces gemstone-grade synthetic sapphires, including the rare blue sapphire.

    stuhrling.com


    The main difference between Krysterna crystal and regular sapphire crystal is the material used to make the crystal. Krysterna crystal is made from a synthetic sapphire material, while the regular sapphire crystal is made from natural sapphire. This means that Krysterna crystal is less expensive than regular sapphire crystal, but it is not as hard or scratch-resistant. Overall, Krysterna crystal is a good option for those who want the benefits of sapphire crystal without the high cost.

    Hardlex Crystal

    Hardlex crystal is a type of mineral glass that is used by Seiko in many of their watches. It’s a bit different from traditional mineral glass in that it’s more durable and scratch-resistant.

    The reason Hardlex crystal is so durable is that it’s made by heating the glass to a high temperature, which causes it to become harder and more resistant to scratches. It’s not as hard as sapphire crystal, but it’s still a great option for those who want a crystal that can withstand everyday wear and tear.

    One of the biggest advantages of Hardlex crystal is that it’s less expensive than sapphire crystal. This makes it a great option for those who want the durability and scratch-resistance of sapphire crystal without the high cost.

    It’s also very easy to care for Hardlex crystal, all you need to do is clean it with a soft cloth and some mild soap and water. It’s not as scratch resistant as sapphire crystal, however, it’s still a great option for those who want a crystal that can withstand everyday wear and tear.

    Overall, Hardlex crystal is a great option for those who want a durable and scratch-resistant crystal that is also affordable. It’s a great option for those who want the benefits of sapphire crystal without the high cost.

    Flame Fusion Crystal

    The Flame Fusion Crystal is a type of watch crystal that is made by fusing a layer of mineral glass to a layer of synthetic sapphire. This process, called flame fusion, creates a crystal that is both durable and scratch-resistant.

    One of the main advantages of a flame fusion crystal is that it is much more affordable than a regular sapphire crystal. This makes it a great option for people who want the durability and scratch-resistance of sapphire crystal without the high cost.

    Another advantage of the flame fusion crystal is that it is also more resistant to shattering than a regular mineral glass crystal. This means that if the watch is dropped or bumped, there is less chance of the crystal shattering and causing damage to the watch.

    One thing to keep in mind is that although the flame fusion crystal is more durable than a mineral glass crystal, it is not as hard or scratch-resistant as a regular sapphire crystal. So, while a flame fusion crystal is a great option for everyday wear, it may not be the best choice for a watch that will be exposed to rough conditions.

    Choosing the Right Watch Crystal for Your Timepiece

    When choosing a watch crystal, there are several factors to consider. These include your personal style, the type of watch, and the intended use of the watch. Here are some tips to help you choose the right watch crystal for your timepiece.

    Choose Based on Your Personal Style

    When it comes to personal style, there are no right or wrong answers. The important thing is to choose a watch crystal that reflects your personal taste and preferences. A domed crystal may be the best choice if you prefer a classic and elegant look. If you prefer a modern and sleek appearance, a flat crystal may be your style. And if you want a high-end luxury look, a sapphire crystal is the way to go.

    Choose Based on the Type of Watch

    The type of watch you have can also influence your choice of crystal. For example, if you have a dive watch, a crystal with good scratch resistance and anti-reflective coating may be a good choice. This will help to protect the crystal from damage and make it easier to read the time in underwater conditions. If you have a dress watch, a crystal with a classic domed or sapphire style may be more appropriate. This will enhance the appearance of the watch and add to its overall elegance.

    Factors to Consider When Choosing a Watch Crystal for Your Collection

    In addition to personal style and the type of watch, there are other factors to consider when choosing a watch crystal. These include the intended use of the watch, the frequency of wear, and the budget. If you plan to wear the watch regularly, a scratch-resistant crystal may be a good choice. 

    If you only plan to wear the watch occasionally, a less expensive crystal may suffice. And if you have a large collection of watches, it may be worth investing in high-quality crystals for your most prized timepieces.

    Conclusion

    In conclusion, the watch crystal is an important aspect of any timepiece. It protects the inner workings of the watch from damage and dust, and it enhances the appearance of the watch. There are several materials and styles to choose from, each with its own unique properties and characteristics. When choosing a watch crystal, it is important to consider your personal style, the type of watch, and the intended use of the watch. By selecting the right watch crystal, you can protect and enhance your timepiece, ensuring that it looks and performs its best for years to come.