This is the Clarus Ware Venus Vase and is indeed a rare item.
Clarus Ware was made Pope-Gosser China. The company was formed in 1902 and began production 1903 in Coshocton, Ohio. Only the earliest examples of their work were marked with Clarus Ware. This vase is listed in the comany's circa 1904 catalog and there is little other reference.
It is 7.5” tall and 3.5” in diameter (measured at the largest part of the base).