Milk glass was first created in the 16th century but has continued to be manufactured to present day. The white glass is generally opaque, with hints of blue, pink or yellow showing through. It’s called milk glass because the glass itself looks like the color of milk. With many glass manufacturers in existence, knowing whether your piece of glass is truly milk glass takes some know-how on your part.
Look at the bottom of the piece and note if it has any markings. Look for manufacturers’ names, such as Fenton, Westmoreland, L.E. Smith Glass, U.S. Glass and Duncan Glass. These manufacturers are legitimate and known makers of milk glass.
Feel the edges of the piece. Is it bumpy or is it plain and flat? While many pieces of true milk glass were made plain with no pattern pressed into them, many were made with decorations. Fenton, for example, was one of many manufacturers to use the Hobnail pattern. This pattern uses many tiny bumps to give a lacey look. If your piece has a Hobnail pattern, and the bottom is marked with a Fenton mark, you can be more certain your milk glass is real.
Look up what other patterns look like. Patterns such as Amber Crest, Emerald Crest, Ivory Crest, Beaded Grape and Old Quilt all are known and sometimes popular patterns pressed into milk glass. Guides such as Collector's Encyclopedia of Milk Glass Identification and Values, by Betty and Bill Newbound and “The Milk Glass Book,” by Frank Chiarenza and James Alexander Slater both offer advice on identifying milk glass and familiarizing yourself with the characteristics of each pattern. Once you know the patterns, and which manufacturers made those patterns, you can be more confident in identifying real milk glass.
Scratch the glass. Use your fingernail to feel the inside of the glass and ensure the piece is true milk glass and not plain glass coated in a white paint or glaze. If it doesn’t feel smooth like glass, it may be coated with a glaze or paint, indicating it could be an impostor.