- The A.H. Heisey Company manufactured world famous glassware in Newark, Ohio from 1896 until 1957. Its celebrated (Diamond H) trademark was known around the world. Today, it is a much sought after glass with collectors world wide. National Heisey Glass Museum Heisey Collectors Of America Inc. Heisey Exhibit at Newark's Institute of Industrial Technology The Diamond H The Factory Company Truck ...my.ohio.voyager.net/~lstevens/heisey