As a Heisey colletor, my favorite two sentences are: "I will not buy unmarked Heisey pieces" or "Heisey was always marked." To begin with, the Diamond H trademark was not designed until around November 1900. This information is based on the data given by A.H. Heisey Company when they made application which was approved, August 8, 1901. The Diamond H was not stamped on all molds until sometime after 1900. Therefore any Heisey glass product produced between April 1896 and November 1900 was not marked.
Starting in the twenties, many pieces were not signed. As well, it appears that some designers believed the mark detracted from the beauty of the design. As a result, the mark grew smaller and was placed in out-of the way places. In addition, some buyers requested the Diamond H be ground off. Heisey used paper labels on many items. Of course, these were removed when the item was used. In order to recognize Heisey without marks or labels, collectors need to research the wealth of material that has been written on Heisey. The Heisey Museum in Newark, Ohio, can assist the beginning collector with many publications. Also museum visits are available.
Heisey blown items usually were not marked, unless a pressed stem was applied or if the item was blown in a mold. Finally, many marks were burned off if the item was held in the "glory hole" too long during the fire polishing technique. In addition, as molds were used, design details, including the mark, wore out.
So, good luck in collecting, and remember not all Heisey was signed!
Note: Address of:
Heisey Collectors of America
169 W Church Street
Newark, OH 43055
Webmaster's Note: This article was taken from the publication "Glass and More, May 1998" with permission from the publisher, Dr. Leonette Walls.