Vintage Green Glazed Ceramic Step Pyramid Bowl Planter Stamped "Made In America"

Vintage green ceramic bowl or planter. This may be a stacking bowl but this is the only one I have. I have not found another example online so I cannot say for sure its original function or if it was a set. It was used as a planter and there are dirt markings inside. I have not tried to soak the bowl but I believe a vinegar soak would remove some of the dirt/mineral deposits. I am unsure if this is safe for food. The bottom is stamped "Made in America". There is one manufacturers blemish to the bottom rim with missing glaze. Doesn't appear to be a chip because it is smooth to the touch. There are chipped areas to the unfinished bottom edge that is not visible when on a surface. Measurements are included in the photos.