Found this in my box of desk trinkets, and thought to share.
From what I remember, my father was given this demo print at some tech show in mid-2000s. I am not sure of the material used for it. The surface is rough, dry, and porous, slightly discolored, but does not appear to be crumbly, flaky, or brittle even after 20 years. My friend suggests it might be made with powder sintering.
Relatively, the tolerances are low and surface is too rough for a true ball bearing like spin, but it does not bind or get stuck.