Explaining the Different Types of Sapphire Mouse Skates

EXPLAINING THE DIFFERENT TYPES OF MOUSE SKATES MADE FROM SAPPHIRE

When we launched SAPPHIRESKATES in December 2021, we were the first sapphire crystal mouse skates on the market. At the time, I knew that some would find the concept of this to be absurd, but I believed in the material despite the higher cost. With this, I fully expected other brands to release sapphire mouse skates of their own. I don't mean to say that others are necessarily copycats. Furthermore, this idea of sapphire mouse skates I do not claim to be truly original, since glass and ceramic skates have been around for a while. However, I do believe that sapphire is the best material for mouse skates, and I am glad to see that others are starting to agree with me.

From the beginning, I have said that there is no best mouse skate on the market. This is still true, but with more sapphire options now available, it's time for an explanation, so you can understand the pros and cons, as well as some manufacturing approaches. I haven't talked much about this previously, but I have looked into similar approaches during the product development process. Again, each of them will have their pros and cons, both from a performance standpoint and from a cost standpoint. In addition, I will give a bit of insight from the perspective of manufacturing them.

(Ngl, the first thing I wanted to try was to take something off-the-shelf and re-purpose it for mouse skates. I was thinking of something like a sapphire bearing. I also considered Rolex date-magnifiers. None of them I felt were ideal, so we took a purpose-built approach instead.)

It's time to embark on the incredibly fascinating world of sapphire. Not only is this an incredible gemstone, its usage also spans so many cool verticals and industries including: watches, lenses, the medical field, and more.

Different Types of Sapphire Mouse Skates

ROLEX-MAGNIFIER / LENS TYPE SAPPHIRE MOUSE SKATES

First, I'll start off with a type that is different from our own product: that is the Rolex magnifier type skate. Early in my texting, I tried these, and they worked incredibly well. There is a brand Cryomods that released this type of skate shortly after I launched Sapphireskates. It's safe to assume they were developing this solution concurrently. These pieces have an excellent surface finish and are relatively affordable. On certain surfaces, the friction will be very low. I initially reached out to a manufacturer who makes these, but decided to pursue other options. The problem is that they are mass-produced using specialized automated machinery and with economies of scale. You will find these in 4 or 5mm, or the odd 5x7mm dimension.

The other thing about this is that they are surprisingly fragile. I have broke these from normal usage, which is something I have never done with Sapphireskates. I believe this is due to the lens' meniscus shape that is intended to conform to the contour of a rounded watch glass. Furthermore, this means that the reverse-side isn't flat and is more difficult to adhere evenly to a mouse base. They are offered only in clear color.

Alternatively, a small sapphire lens can be used, but do note that these watch magnifiers are indeed a type of lens.

(An interesting thing about sapphire lenses is that they can range in cost dramatically, starting at just a few dollars all the way up to insane amounts. While doing research for SAPPHIRESKATES, I even came across sapphire lenses in which a single lens could cost thousands of dollars. The reason for this is for scientific applications in which precision will impact measurements.)

SCREEN-PROTECTOR LENS-PROTECTOR TYPE SAPPHIRE MOUSE SKATES

Next up, I want to talk about a type of sapphire mouse skate that really surprised me. I was not expecting these to come to the market so quickly, but Lamzu pulled it off. Another inspiration for the use of sapphire for my personally, was my sapphire screen protector on my ROG Phone 5. These are made, again, using highly specialized machinery. The surface finish is excellent. It's quite thin too. There are downsides though. As with the rolex glass, this approach suffers from being less durable. It's also custom-built to fit the particular mouse it's intended for. I am not sure about others aside from Lamzu at the time of writing. This means it can't be re-used on different mice. I could not consider this custom-built approach, as it was simply inaccessible to me. Perhaps more importantly, if a customer is going to spend on aftermarket skates, it would be better if they can use them on other mice.

The benefit of this approach is that you get something super-fitted with high surface area. I will write an entire article on the topic of surface area, but will summarize for now:

• For simple measurements of static friction, surface area doesn't matter and won't affect the coefficient of friction. The reason for this is that if you reduce the surface area, it will increase the actual area of contact.
• If you apply too much force on the mouse, it will introduce a second type of "dig" friction. Therefore, those with a heavy mouse or heavy hand will definitely want to consider higher surface area solutions compared to something like SAPPHIRESKATES.
• The downside to high surface area is that you are significantly increasing the weight of the mouse, especially when using a material like sapphire.
• Believe it or not, using high surface area with a material like sapphire actually does not prevent wobble of the mouse.

Despite these skates being likely mass-produced, it's still not as straightforward as injection-molded plastic or ceramic. You are still dealing with single-crystal sapphire. I am not sure if they are using a layered approach combining another material with a thin piece of sapphire.

GEMSTONE-TYPE SAPPHIRE MOUSE SKATES

The third type of sapphire mouse skate is the gemstone type. This is the type that we use. The approach is quite different from the others: it starts off with a relatively large boules of gemstone-grade sapphire, ruby, or other types of crystal. It is then cut into a specific shape and size. This is done using a diamond saw. The surface finish is then polished to a mirror finish. This is done using a series of increasingly finer grits of diamond paste.

Starting with whole raw crystal and gradually whittling it down and shaping it does seem to improve durability, and gives and end-result that can't be achieved through other approaches. The downside is that it is a very manual process. It is also very time-consuming. This is why it is more expensive. However, the process offers more flexibility due to it being a mostly hand-made process. This means that we can offer custom sizes and shapes. We can also offer different colors.

I mentioned that sapphire usage in a variety of industries. Thus, there are specialized automated machinery that exists for sapphire crystal growth, cutting, and polishing to produce components for semiconductors, watch glass, and everything in between. However, these machines can cost millions.

In order for us to purposefully design a mouse skate, we need to be able to control the shape and size. This is why we took this gemstone-type approach.

I want to reiterate the fact that this process produces real gemstones starting from whole crystal. With that, there is a multitude of colors that can be use without any coatings or treatments required. In order to produce colored sapphire or ruby (both are the same crystal: corundum), via a process called doping. This is a process where a trace amount of another element is added to the crystal (the "dopant"). This is done during the crystal growth process. The most common dopants are chromium, iron, titanium, and vanadium. These are used to produce blue, green, pink, and purple sapphire respectively. The most common dopant for ruby is chromium. This is used to produce red ruby. The color is in the crystal lattice structure itself, and will not fade or change over time.

There is more to it than flexing. Despite these colors being very beautiful, there is a pragmatic reason for using colored sapphire rather than clear. Watchmakers have been using ruby jewel bearings for centuries and continue to use ruby today, despite clear sapphire being readily available. This is because ruby is much easier to see when assembling the watch and won't get lost as easily.

WHICH TYPE OF SAPPHIRE MOUSE SKATE IS BEST?

After testing mouse skates of all types, materials, and sizes over the past few years, I have learned much about friction. I have also learned that there is no one-size-fits-all solution. It's more than just being about preferences too, it's about tradeoffs.

Sapphire is simply a material. It's quite a good material for the purpose of mouse skates, but a material alone isn't what makes a mouse skate good. It's the combination of the material, the shape, the size, and the surface finish. Additionally, a material alone can't determine its friction. It's the interaction with the surfaces of two objects.

Within this interaction, there are several forces that can affect the friction. The first is what people traditionally think of as friction, which is simply about how much contact the surfaces are making with each other. (In actuality, objects truly don't make "contact" with each other: atoms can't occupy the same quantum state as defined by the Pauli Exclusion Principle, so as they get closer, there are more and more electrons that are repelled by the other electrons.) There are other overlooked causes of friction that are relevant to gaming mice. These include:

• Moisture can cause friction via the Van Der Waals force.
• Macroscopic imperfections such as dust and debris. This is why mouse skates perform best if the edges are rounded.
• Electrostatic friction. Static electricity can truly be a source of friction, so you may try to discharge your mouse and mousepad if you suspect something.
• The elasticity of either the mouse skates or mousepad. I'll get to this more in a bit.

There are other factors too, but before you worry too much about requiring a degree in order to understand this, the good news is that you don't need to. You can easily test static friction by doing a sliding test on your mousepad with your mouse/skates. You can test dynamic friction simply by applying some consistent force to the mouse. I would also argue that you don't need to do any of this: you can simply feel how the mouse feels and decide for yourself.

Getting back to the topic of which mouse skates made of sapphire are best, first I want to talk specifically about the material. This aspect will be true regardless of which brand of skates you choose. Sapphire is a very hard material that can be polished to a very smooth finish. This means that the microscopic ridges between the atoms are very small. People often ask me if they can use SAPPHIRESKATES on a glass mousepad. I'd say that it works, but there's no way that I can gaurantee you won't scratch the glass. Two hard rigid materials interacting results in initially very low friction, but if micro-scratches form, friction will increase.

You may have noticed a trend in which people pair something like PTFE skates with a glass pad, and sapphire with a cloth pad. There's a reason for this: elasticity. Elasticity is the ability of a material to deform under stress and then return to its initial shape. This is known as "elastic deformation" whereas permanent changes are called "plastic deformation".

For maximum low-friction, you ideally want hard surfaces. But you can see how two hard surfaces can create some problems (by the way, personally I use sapphire with a polycarbonate pad as it offers just the right amount of elasticity to safely slide away from the sapphire).

Next up are the attributes that make up what a mouse skate makes a mouse skate. Surface area is about tradeoffs between the following:

• High SA = less chance of dig but more weight
• Low SA = the same level of friction as high SA but less weight and more chance of dig.
• High SA = greater chance of encountering debris on the pad, but less chance of encountering debris on the mouse.

For things like stability and wobble, you may be surprised when I tell you that surface area doesn't necessarily affect this, and can at times even negatively impact stability as you increase SA.

You would think that a flat large set of skates would make more points of contact with the mousepad, but this is not the case. The reason is that the mousepad is not flat. It has a slight curvature to it. This curvature is what allows the mouse to glide on it. If you have a flat mouse skate, it will not be able to follow the curvature of the mousepad. This is why you need to have a concave shape to the mouse skate to ensure contact.

Furthermore, a mouse base will not be perfectly flat. When glass skates were first released by LGG (I believe), this was something they stated in their product page so I assume that it caused issues for some.

Anyways, you can see for yourself by putting something like a card on your table and viewing from a side angle. You will see that the card does not sit perfectly flat. A flat plane is not a real thing, but a mathematical construct. However, this definitely doesn't mean that it's a bad design whatsoever. As the mouse moves around, the weight simply shifts from one part of the plane to another.

If you truly want to guarantee that all mouse skates make contact with the surface, this is only possible if you use 3 skates. As you increase the number of contact points, the chance of each point touching the surface will decrease. However, not many people would consider using 3 skates. The lateral stability decreases if you go too low. That is why cars have 4 wheels but camera tripods have 3 legs.

You might be thinking: I have flat glass mouse skates and it's making full contact. You are not correct but you may have the right idea if you are using a cloth mousepad. Cloth mousepads allow for that elastic deformation I mentioned earlier, which will increase the points of contact and thus increase stability.

This concept is illustrated vividly in F1 racing. Teams have to utilize the right strategy when choosing between hard or soft tires. Perhaps counter-intuitively, soft tires let drivers go faster. That's because they provide a lot more grip to the track (and thus, stability) than hard tires. Hard tires are more durable.

Now you can see why there is no single best mouse skate. It's all about tradeoffs. However, there are things that are important no matter what:

• Not too thick or too thin. Too thick and you will be close to the LOD cutoff. Too thin and the sensor is too close to the surface and won't track optimally. In modern sensors, there really isn't a loss of accuracy though, as long as you are within the LOD cutoff.
• Note: for smaller SA skates ("dot" skates) you have to trust me on this: you'll want to go a bit thicker than large SA skates. The mouse has a natural flex to it. This is not a bad thing, because you want the mouse to be light. But if you are using a small SA skate and applying pressure, the center of the mouse is going to go down and maybe even touch the pad.
• Rounded edges are absolutely essential in order to maintain low friction and overall smooth performance.
• Uniformity is important. We do extensive QC on all of our pieces and match them within hundredths of millimeters. That being said, you can't control all variables like mouse base flatness, table flatness, etc. So don't sweat it too much and there are plenty of ways you can adjust.
• Surface quality is an interesting one. This relates to the depth of the microscopic troughs in a surface. For our match-grade SAPPHIRESKATES, we polish down to 0.12 microns. So it's a very good surface finish. I'm sure other brands have a good surface quality too. The odd thing is that this doesn't necessarily always reduce friction. In fact, if two very smooth surfaces touch, they can actually form an extremely strong bond. But it's safe to say this won't happen with your mouse skates and mousepad.

I hope this helps. I'm sure I missed some things, but I think I covered the most important ones. If you have any questions, feel free to ask!

-philzgoodman