I have this bowl in the small and large sizes. In the antique store where I bought them, it was together with a medium bowl in the Butterprint pattern, I think. I didn't buy the medium bowl.
Hmm, Amish Butterprint has a print on all four of the Cinderella mixing bowls. I would guess that it is part of the Horizon Blue Cinderella Mixing Bowl set. There are two plain blue bowls and two white with print bowls. I must say that the plain Horizon blue is probably my favorite Pyrex blue (not aqua/turquoise).
I think it IS a Horizon. Thanks ladies!
Definitely a Horizon bowl!