What type of Rock could make this spehere

I am a marble guy. Dozens of people come to me weekly with questions on identification. I can Id most marbles made, even those with shearing errors, rolling errors where 1 marble is formed from 2,3 or even 4 and encompassing a size and pattern not known for by the company......

HOWEVER
Rocks.....Jesus. I can barely tell quartz from a quarter
So, I get a few images with spheres in them. I se this from tiem to time and with a little bit of google I can usually tell what rock type I am looking at. AGAIN, this is an articulation issue in finding out a stone type....

But this is CLEARLY not a marble and, in my view, a clay creation. HOWEVER, in the presence of being thorough, I submit the image for rock fans to view and toss out input
I see a "tail" which is common to hand made marbles. It is a transitional tail, however, there is no glass that does this to my knowledge. Any input or agreeance that this is clay or some other stone I am unfamiliar with ?
Thank you for your time