Hi. This is actually called a "Crumb Knife" and sometimes referred to as a "Crumber". It was used instead of a Crumb Brush, to properly remove crumbs from the table during the course of a meal at restaurants, or in homes by staff.
I am sorry but I cannot make out the Silver Hallmarks on this with the current picture. May I suggest that you take a picture again with "natural light" and no flash on then post on here.
Depending on who made these and the patterns, they can get pricey.
