I don’t know but if I look textures with a certain distance and angulation, sometimes I see this:
You can see a “noise” on the texture, and sometimes this noise can be harder.
What causes it?
Try increasing the aniso level in the texture import settings: Unity - Manual: Texture Import Settings
What you’re seeing is a Moiré Pattern. In general for game engines, it’s caused when a texture with some sort of pattern to it mixes with another pattern. For example, a checkerboard pattern can display this problem very noticeably simply by being viewed from a steep angle. The limited number of pixels available to display the pattern on-screen results in the texture skewing in this manner.
An additional potential cause, however, comes from shadows. Potential solutions to this can be found here. In general, tweaking shadow settings on lights can potentially solve, or at least mitigate the problem.