Milk glass is identifiable by its milky white color and its patterns and shapes. Collectible milk glass became popular in America in the mid-1800s, and it reached its highest popularity at the turn of the century.
Popular shapes of milk glass included dolphins and later, birds. Common patterns included "block and fan" and "buttons and arches," as well as ribbed grapes and drapery patterns reflecting major events of the day. Glass from the 1800s is a duller, more opaque white than later examples, although some pieces may be translucent at the edges.
Newer pieces have a rich, milky white color. Common patterns include hobnail and paneled and beaded grapes. The most commonly collected milk glass originated in mid-20th century, and the pieces often have the manufacturers' stamps on the bottoms. Major manufacturers include Fenton and Westmoreland.
Milk glass has been in production since the 16th century, but most of the milk glass found in modern times dates from the 1840s and later. Rare examples of 19th century milk glass are considered very valuable, and early 20th century milk glass is also sought after. In the 1950s and 1960s, milk glass became very popular, and there are many mass-produced pieces from this time period. Although they are very attractive, these later pieces are less valuable.
The age of a piece can be determined by the maker's markings, the patterning and the color. Milk glass in a color other than white (pastel green, blue, purple or pink) means that it probably dates from the 20th century; this is when adding dyes to milk glass became very prevalent. Milk glass can be difficult to accurately identify yourself, and if you have a piece you are unsure about, the best course of action is to take it to an antiques appraiser who can help you determine the provenance and value of your piece.