The toy consists of a heavy, thick chrome plated steel disk, a slightly concave, mirrored base, and holographic magnetic stickers which can be placed on the disk. The disk, when spun on the mirror, exhibits a spinning/rolling motion (or spolling, a blend of "spin" and "roll"), slowly moving through different rates and types of motion before coming to rest – for example, the precession rate of the axis of symmetry accelerates as the disk spins down. Euler’s Disk has an optimized aspect ratio and a precision polished, slightly rounded edge to maximize the spinning/rolling time. A coin spun on a table, as with any disk spun on a relatively flat surface, exhibits essentially the same type of motion, but is normally more constrained in the length of time before stopping. The Disk provides a more effective demonstration of the phenomenon than more commonly found items.M is the mass of the disk, and mu is the dynamic viscosity of air. More at Wikipedia.
...the total spinning time is
where is the initial inclination of the disk.