This is a vase grinder.
It is from Memphis. The craftsmen making pots from soft Egyptian alabaster or harder stone had limited tools. They shaped the outside of the pot first, then drilled out the centre of the pot using a hollow drill. They would have had a number of winged grinders like this, of different sizes. These were held in a forked stick, and turned to hollow out the inside of the pot. Sand was probably used as an abrasive to speed up the process. This is a vase grinder. It is made from quartzite stone. We do not know how old this object is.