Greek with hole in head...

For a second there I thought this was a post about k e mper

I think you have another part to a lamp. The knob to adjust the wick.

Cliff

I don't think it is the wick adjusting knob from an oil lamp. I have found many of them. Typically they are approximately the diameter of a dime and constructed of one piece of brass on a shaft.

This piece is larger than a quarter, made of two layers of thin brass and most likely not a lamp wick knob. The hole is too big, the diameter and construction are not consistent with a wick knob...

Its purpose is most likely different -- still perhaps a part of an oil lamp, but different than the knob you suggest.