Clay Composition Pokerchips were introduced circa 1880. The Catalog section in the back of Dale Seymour's guide Antique Gambling Chips has a page from a Samuel Nafew catalog dated 1895 with your chip pictured in the advertisement with four other embossed "DIAMOND" chips offered by Nafew in 1895. I am not certain if Nafew made poker chips or if they were just a retailer.

Samuel Nafew Co.
392 Broadway
New York
&
167 Dearborn Street
Chigago

Dale place a value of D on the chip $4 to $5 but most Antique chips need to be in near perfect condition to bring book value.