Grandma's pen

This belonged to my Grandmother around the turn of the last century.
The pen looks to be mother-of-pearl and a gold nib. The mfg. of the nib and maybe the pen, is Benj. Allen & Co., Chicago.
The pen has been in the box for as long as I know, but is not the original container. The box lid has the inscription: Sheaffer Self Filling Fountain Pen-----W.A. Sheaffer Pen Co.-----Ft. Madison Iowa U.S.A.