Vtg buying Norton Abrasives Crystolon Oilstone Sharpening Stone 7-3/4

Product Name: Vtg buying Norton Abrasives Crystolon Oilstone Sharpening Stone 7-3/4
An early Crystolon oilstone made by Norton Abrasives. Great vintage sharpening stone from my Dad's tool collection. Most likely from the 1930's/1940's, but buying can't be sure! Sold as is. No warranty from the seller. No Returns. CONDITION NOTE: Used with the original box and in good condition for its age. Includes the original box (which is very oily and shows edge/shelf wear and the label is missing pieces), but not any related documentation (see pictures). See detailed high resolution (zoom-able) pictures to know what you are purchasing.