CD 145 HEMINGRAY - 21 telegraph insulator with a coin shaped dome depression

Take time to pay a little closer inspection of your collection. Going thru a collection I bought earlier this year, I came across this piece.

Teepee dome HEMINGRAY - 21 with sharp drip points in HEMINGRAY blue. Top of dome has a round depression a little smaller than a dime. No "coin-like" impression details can be seen. Has the same texture as the surface of the piece. Smooth in it's overall appearance. Does not appear to have been ground into the surface. Appears the object may have been some type of "slug" thrown in the mold that fell out when the insulator was formed and removed. Kinda neat piece, just glad I was looking a little closer to details today.