08/29/2026
Ever a leader in marketing, Heisey was one of the first glass companies in the United States to mark its glass pieces with a trademark. The iconic Diamond H found on many Heisey pieces was designed by A.H. Heisey’s eldest son, George Duncan Heisey around 1900. He modeled it after his fraternity’s (Psi Upsilon) diamond symbol. Shortly after designing the Diamond H, the Heisey Glass Company began using it in advertisements and it was officially registered by the U.S. Patent Office on August 6, 1901. Originally the mark was large and placed in a prominent location, usually the center bottom of a piece. An advertisement from 1913 directs the buyer to look for the mark on every piece as a type of hallmark that guaranteed quality glassware. Over time the mark became smaller and the placement could vary. Sometimes it is found behind a foot or on a stem or rim. Occasionally the mark appears on both sides of a divided item like a two-part relish. Not all pieces of Heisey glass made after 1900 are marked in the glass. Later advertisements acknowledged this fact by stating the mark was either “embossed on the glass or on an adhesive label.” The Diamond H remains an enduring symbol of the company and adds an exciting element to the search for Heisey glass by collectors today.
Learn more about the Diamond H and the Heisey Glass Museum at our website here: https://heiseymuseum.org