Before 1973, Fenton glass creations were marked with a variety of paper labels. Since then, its products have had a raised logo molded directly into the glass, according to About. The stick-on labels were easily removed or worn away by handling and cleaning. Photos of the permanent oval marking that replaced the paper labels can be found within the Classic Era Makers Marks section at Ddoty.
Though many Fenton pieces have an inherent look, others must be carefully researched to confirm the maker. The firm began in 1905 as a glassware-decorating business, painting designs on blanks made by other companies. Fenton carnival glass was inspired early on by glass masters such as Steuben and Tiffany, and more than 130 patterns have been produced, according to Schroeder's Antiques Price Guide.
During the lean World War II years, the company was kept running by producing utilitarian kitchen glassware, such as mixing bowls and juicers. In the late 1940s, Fenton family members dedicated themselves to advancing the business, and by 1986 a third generation stepped in to continue producing collectibles admired worldwide.
The unique Hobnail line of milk-colored glass was developed in the early 1950s. When an unsigned piece has been researched and identified as Fenton, the value can be determined based on current market prices.