Mineral vs Sapphire Crystal – A Comparison for Watch Glass

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We are Romlicen, a Chinese watch manufacturer that provides OEM, ODM watch manufacturing services, custom logo watches and more. In this article, we aim to help potential clients who are looking for ODM or OEM services, or want to create their own watch brands, understand the key differences between mineral and sapphire watch crystals.

When choosing a watch, one of the most important but often overlooked components is the watch crystal. The watch crystal, also known as the glass, covers the dial and protects the internal mechanisms. There are different materials used for watch crystals, with the two most common options being mineral glass and sapphire crystal. Both have their own advantages and disadvantages. Understanding the key differences between mineral and sapphire watch crystals will help you make an informed decision when purchasing your next timepiece or creating custom branded watches.

In this article, we compare mineral glass versus sapphire crystal across a number of categories including scratch resistance, impact resistance, clarity, cost and more. We also provide tips on how to tell the two materials apart. Our goal is to educate watch buyers so you can select the best crystal material for your specific needs and budget. Keep reading as we dive into the mineral vs sapphire crystal debate in detail!

sapphire crystal watch 02
Sapphire Crystal Watch

Mineral Glass

Mineral glass, as the name suggests, is made of various mineral materials. The primary mineral components of basic mineral crystal are silica and soda lime. It goes through a heat treatment process to increase hardness and durability.

Mineral watch crystals rate about 5 to 7 on the Mohs scale, with 7 being the highest end. This means mineral glass is prone to scratches and scuffs over time with regular wear and tear. While not as scratch resistant as sapphire, mineral crystal is less brittle. It can withstand bumps and impacts without shattering or cracking in most cases.

The advantages of mineral glass are that it is affordable, transparent, and relatively durable for daily activities. It offers good optical clarity to clearly display the watch dial details underneath. However, with lower Mohs rating, mineral crystal can lose its clarity faster and appear hazy when extensively scratched. It also lacks the luxury finish and cachet of sapphire.

For budget-focused consumers or basic timepieces that don’t require heavy-duty performance, mineral watch crystals present a cost-effective option. They sufficiently protect the watch without expensive over-engineering.

Sapphire Crystal

Sapphire crystal is synthesized from aluminum oxide powder into a crystalline form. It shares the same molecular composition as natural sapphires, making synthetic sapphire extremely durable and scratch-resistant.

With a Mohs rating of 9 out of 10, sapphire crystal is the second hardest material after diamonds. This supreme hardness provides unmatched scratch protection for watch faces. Virtually nothing except diamonds can leave a mark on a sapphire crystal. Even strong materials like steel and quartz will not damage or cloud a synthetic sapphire timepiece.

In addition to scratch resistance, sapphire possesses excellent optical clarity thanks to its single crystal structure with tightly packed atoms. It maintains transparency without becoming tarnished or discolored over time. The crisp, clear view of watch dials through a sapphire lens is unparalleled for decades into the future.

While synthetic sapphire costs significantly more than mineral alternatives, its longevity provides superior value for discriminating buyers. Sapphire crystals elevate fine watches into enduring keepsakes with vintage appeal. Overall, its combination of hardness, clarity and aesthetic quality puts sapphire in a class of its own for upscale timepieces.

sapphire crystal watch 01
Sapphire Crystal Watch for women

How to Distinguish

There are a few easy ways to determine whether your watch crystal is made of sapphire or mineral glass. Here are a couple of simple tests you can do at home to tell the difference:

The Water Drop Test
Simply place a small droplet of water on the surface of the watch crystal. If the water beads up in a round shape, the crystal is sapphire. If the water flattens out more, it is mineral glass. This works because of the higher surface tension on sapphire crystals.

How to tell mineral glass from sapphire crystal

Check the Side Coloration
Look at your watch crystal from the sideways profile. Sapphire crystals have a transparent, colorless or icy-white color. Mineral crystals tend to have a green, blue or purple tint around the edges. This is due to mineral glass containing traces of iron oxides. The tinted edges are not as visible from the top view.

The difference of Sapphire crystal and mineral glass for watches

Test with a Knife Tip or Hard Metal
Try gently scratching the watch surface with a knife tip, key or another hard metal surface. Keep in mind that metal items can still damage softer mineral crystals. But if your watch resists metal scratches, it most likely confirms the durability of sapphire crystal. Avoid excessive scraping attempts as this could still damage the watch over time.

The Cold Touch
Mineral glass often feels warmer to the touch than the very smooth, icy surface of sapphire. This temperature variation is subtle but can also help identity a sapphire crystal on your watch.

These are quick, easy methods anyone can use to determine whether a watch features a mineral or sapphire crystal. If still unsure, always check the watch specifications from the manufacturer.

Mineral vs Sapphire Crystal for Watches
Mineral vs Sapphire Crystal for Watches

Scratch Resistance

When it comes to scratch protection for watches, sapphire crystal is unmatched while mineral glass is more prone to surface damage over time.

As mentioned earlier, sapphire has a Mohs rating of 9 out of 10 in terms of hardness. This approaching the hardness of diamonds makes sapphire crystals extremely scratch resistant. Except diamonds or other sapphire crystals, there are virtually no materials that can leave a scratch or blemish on a synthetic sapphire watch surface. Its scratch resistance even exceeds that of steel watch cases.

On the other hand, mineral crystal rates between 5 and 7 on the Mohs Scale. While special treatments can improve its scratch resistance, mineral glass still cannot compare to the near-impenetrable surface of synthetic sapphire crystal. With daily use, small scratches accumulate faster on mineral glass watch faces.

For luxury watches or timepieces meant for rough outdoor use, sapphire crystals provide the ultimate protection and durability. They keep watch dials pristine and crystal clear through years of continuous wear. While mineral glass suffices for light duty dress watches, sapphires live up to heavier demands from active lifestyles. Their scratch proof nature retains high-quality aesthetics far longer.


When assessing the durability of sapphire versus mineral watch crystals, there are a few key factors at play.

Firstly, sapphire earns its reputation for being ultra-durable against scratches and daily wear. So in terms of surface durability over an extended timeframe, sapphire crystals excel. However, sapphire is more brittle, making it prone to shattering if subjected to a hard knock or excessive impact. When sapphire breaks, it cracks in a spectacular spiderweb pattern.

By comparison, mineral glass is tougher against impacts and shocks. It has higher shatter and crack resistance thanks to more flexibility in its molecular structure. While it succumbs easier to surface scratches and abrasions, mineral crystal better handles drops and bumps that would severely damage or destroy sapphire crystals.

So in summary:

  • Sapphire Crystal – Extremely durable against surface scratches but higher chance of shattering from sudden impacts
  • Mineral Glass – More prone to scratches but increased shock/impact resistance resulting in a lower shatter rate

When choosing your watch crystal, you need to weigh your expected use cases and choose accordingly. Activity-prone lifestyles may benefit from mineral glass while buyers wanting lifelong scratch protection would prefer sapphire. Understanding these durability tradeoffs allows you to pick the best option.


Transparency and Clarity

High optical clarity is a key benefit that synthetic sapphire crystals offer over mineral glass. Sapphire rates extremely high on light transmission and transparency due to its tightly packed crystal lattice structure. It maintains see-through visual acuity without hazing or yellowing over time. This allows sapphire-faced watches to showcase the beauty of intricate dial details for decades into the future.

While mineral crystals start out with decent transparency, they lose clarity faster with accumulated scratches or cloudiness from oxidization and environmental factors. Mineral glass can take on a frosted, opaque appearance over years of use—obscuring the watch face visibility. On the other hand, quality sapphire retains its like-new flawless optics and readability for life.

Superior transparency becomes especially apparent in dive watches or other demanding environments. Underwater visibility suffers more quickly with mineral glass whereas sapphire provides reliably crisp time display at a glance—even at night or murky depths.

So for those desiring an enduringly clear portal to their watch’s visual aesthetics, sapphire is in a league above mineral glass. Sapphire provides the closest thing to a lifetime clarity guarantee.

Cost and Value Comparison

One of the biggest differences between sapphire and mineral watch crystals lies in the pricing. Sapphire crystals generally cost at least 5 to 10 times more than similar sized mineral glass pieces.

Why such a large gap? Producing flawless synthetic sapphire requires extensive processing under extreme heat and precision cutting. Sapphire’s unparalleled hardness also demands diamond-coated grinding tools addition to high tech equipment. These complex manufacturing demands drive up costs substantially.

In the watch world, this produces a huge price spectrum based on crystals alone:

  • Basic mineral glass watches – $50 – $500
  • Sapphire crystal watches – $500 – $5,000+

While the upfront investment is higher for sapphire, many buyers find it worthwhile given the tremendous value sapphire adds. By virtually eliminating scratches, sapphire crystals maintain pristine new condition and significantly extend a luxury watch’s lifespan—keeping both functionality and resale value high. Well-cared for sapphire watches become family heirlooms.

Overall the combination of status, beauty and durability make premium sapphire crystals a sound value-add for discerning buyers. The optical clarity, scratch proofing and timeless aesthetics warrant the higher price tag for sapphire crystals.

Summary and Key Takeaways

To recap this in-depth comparison guide, let’s revisit some of the major differences between mineral and sapphire crystals for watches:

Scratch Resistance:

  • Sapphire is exponentially more scratch resistant owing to its 9/10 hardness level. Virtually indestructible outside of diamonds.
  • Mineral glass scratches easier from daily wear and abrasions over time.


  • Sapphire excels in surface durability but is susceptible to shattering from impacts.
  • Mineral glass is less durable against scratches but better handles drops or blows.


  • Sapphire remains optically flawless and crystal clear for life thanks to its tightly packed structure.
  • Mineral glass loses clarity quicker when scratched and can become permanently hazy.


  • Sapphire crystals are around 5-10X more expensive than mineral equivalents.
  • But sapphire offers tremendous long term value by extending a watch’s like-new aesthetics and performance for decades.

When selecting a fine timepiece, carefully weigh your personal priorities—whether ruggedness, scratch-proofing, clarity or investment lifespan. This determines whether premium sapphire or economical mineral best suits your wrist. For many buyers seeking life lasting quality, sapphire’s virtues outweigh the steeper entry price.

Hopefully these mineral vs sapphire crystal comparisons provide a helpful cheat sheet when shopping for your dream watch. Let me know if you have any other questions!

Sapphire Coated Mineral Glass

For those seeking the durability of sapphire but hoping for some cost savings over a pure sapphire crystal, an alternative choice is to consider sapphire-coated mineral glass.

As the name describes, these hybrid crystals consist of a mineral glass core with an exterior sapphire coating applied via a specialized deposition process. The end result provides enhanced scratch resistance and hardness approaching that of solid sapphire crystal but at a lower price point.

Sapphire coated mineral glass offers other advantages too. The mineral core better absorbs impacts while the sapphire layer provides impressive scratch protection close to a full sapphire timepiece. This innovative fusion brings out the best performance qualities of both materials.

The layer of sapphire on these composite crystals can vary from a thin coating up to 1.5mm tick. In general, the thicker the sapphire, the greater the durability it will add to the underlying mineral core. But even a fractional sapphire finish makes a noticeable difference in resisting scratches, scuffs and abrasions during everyday use.

Overall, sapphire coated mineral glass presents attractive qualities at reasonable investment levels. For many buyers, these composite crystals deliver the ideal combination of toughness, optical clarity and value in a watch. They split the difference nicely between low-end mineral glass and high-end pure sapphire pieces.

Sapphire Coated Mineral Glass
Sapphire Coated Mineral Glass

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At Romlicen, we design and manufacturer exceptional timepieces with quality sapphire and mineral watch crystals to meet diverse preferences.

If you like the sound of these stunning watches for women and men, browse more of our catalogue today. We produce fine quality timepieces that make meaningful gifts as well as valued personal accessories. They represent years of reliable service whether given as a reward, memento or treat for yourself.

Own a dazzling conversation starter on your wrist. Our sapphire and mineral crystal watches deliver lasting style and accuracy that always impress. Let us adorn you with an accessory built to turn heads now and hold memories in the decades beyond!

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