Distinctive glassware markings include a plain or circled cursive letter L, among the Libbey hallmarks, and the letter J within a square signifying Jeannette glassware from the 1940s. C in a single or double circle marks Chattanooga Glass Company pieces, found on Coca-Cola bottles once manufactured by the company.
A marking of D.P.B. is found on the light green beer bottles produced by the Deer Park Brewing Company in New York in the early 1900s. An F in a hexagon references Fairmount Glass Works, which manufactured in Fairmount, Indiana, from 1889 to 1906 and in Indianapolis from 1906 to 1968. A cursive F in a vertical oval signifies the work of the Fenton Art Glass Company of Williamstown, West Virginia. Marketing glass since 1905, Fenton did not introduce this mark until 1983.
Another distinctive glassware symbol is a marking of 3 R followed by a five-point star, which signifies the work of the Three Rivers Glass Company from 1928 to 1937. The Lamb Glass Company was noted by the letter L with the number 52 tucked inside it, or the letter L followed by a hyphen and 52. The W.J. Latchford Glass Company, which produced glassware from 1925 to 1939, used two markings: a capital L in a rectangle and a capital L in a shield.