“Sad” is an Old English word for “solid,” and the term “sad iron” is often used to distinguish the largest and heaviest of flat irons, usually 5 to 9 pounds. - says 'Collectors Weekly'.
If to be used as an iron, the last photo will be of interest. The
base feels smooth to the touch, especially the pointed end, but could do with some buffing of some
kind if it is for use.