I've come to realize recently that I am almost always preferring thinner mousepads because they provide a more consistent glide for me, as I tend to put more force into my swipes and more weight into the mousepad than most people.
However, the Shiden is the one exception so far where I think the thicker option is actually preferable. We all know it's a very quick pad, so had just a little give to the surface helps the subtle texture of the Shiden come out in a very nice way, that not only makes it pleasant to glide on, but actually provides enough feedback to stop almost as quickly and precisely as your QCK type cloth pads (with a good bit of practice with it). Yet the Shiden's unique surface has much more 'surface tension' than any of those cloth pads, so unlike them, a thicker base doesn't give the Shiden an entire wide range of glide speeds that depend on the pressure you on the mouse (this is where the softer Hayates and QcK Heavy fall down, in my opinion).
Artisan's famously bewildering and amusing English translations make it hard to tell exactly what the Shiden is, but parsing what they provide online with my experience using it and at least a decent knowledge of material science as it relates to mousepads, I think I have a pretty good guess on the Shiden. Everything beyond this point is merely an educated guess.
The 'core' of the surface is some kind of fiberglass-woven (polyester?) cloth
, which can be made suitably thin enough (0.1mm). This could explain the 'glittery' appearance of the surface, though it wouldn't surprise me if they added some flecks of a reflective metallic compound to pigment the surface resin (for aesthetics presumably). And why Artisan would try to describe it as glass surface or glass coating.
This fiberglass cloth is set in a non-reinforced, unsaturated polyester resin
that not only gives the surface the unique, "hybrid" feel, but also bonds the top surface to the rubber base. The "hybrid" feel comes from the polyester resin that fills in and smooths the cloth weave as it cures, and even though this gives it the fast, slick, firm feel of a hard pad, there is enough pliability that it is reminiscent of a cloth pad. And because the thin resin is almost more like a coating on the fiberglass cloth, the texture is still perceptible and helps immensely with it not feeling alarmingly unwieldy and uncontrollable like a true hard pad.
Finally, I think the weave of the fiberglass cloth is similar to gabardine
or twill, which is a relatively coarse pattern that would be pretty slow on it's own (I think the tortoise-like Artisan Hien uses a similar weave), but would work well with a resin or coating to fill it in and even it out. It's darn near impossible to make out any details about the weave with the naked eye or pictures though, largely due to its high reflectivity and the resin & cloth being extremely similar in color.