Ask About Antiques/Opalescent Glass: The Pearl Of Any Collection

by Budd A. Moore, Ed.D.

Opalescent glass is a generalized term for clear and semi-opaque pressed glass, cloudy, marbled, and sometimes accented with subtle coloring all combining for form a milky opalescence in the glass. While Rene Lalique may be recognized by most as the pinnacle of opalescent glassmaking, stained glass first evolved in the late 1800s and early 1900s during the Art Nouveau period when American glassmakers transformed European stained glass used in cathedrals into the translucent milky glass we now refer to as opalescent. John LaFarge and Louis Comfort Tiffany were two American artists who first experimented with opalescent effects, driven by their desire to use glass in creating beautiful visual scenes in art without painting. Opalescent glass was first developed and patented by John LaFarge in 1879, but it was Tiffany who created the masterworks in glass for which he is still so well known today. Tiffany created totally new colors in glass, new types of glass unparalleled in depth and coloration, and used glass in new forms that evoked the forms of nature.
The opalescent effect is a glassmaking technique used by many manufacturers to greater or lesser degrees of artistry, produced in the cooling process which creates the milky opalescent effect which illuminates any coloration when light shines on it. Sometimes the opalescent effect was created along the edge of a piece, often coupled with wavy effects and making for an elegant yet subtle look. This opalescence is also created in the glassmaking by alternating heating and cooling of the glass and with the addition of chemical additives to create the desired effect. Many U.S. manufacturers made this type of opalescent glass, most notably Fenton, Northwood, Hobbs, and American Glass, while Davidsonís was the major European manufacturer based in the U.K. and giving their wares the marketing name of Pearline. There is also a type of opalescent glass which is made in layers, and again the heating and re-heating process is used to create the opalescent effect with the addition of chemical agents. The degree and location of the opalescence is controlled as such by the glassmaking process, and by the thickness of the glass itself as it forms itself in the molds.
Given the intricacy of some of the designs, the production of the metal molds in sufficient detail was an important part of the process. Many of the molds for French opalescent glass of the Art Deco period were done by Franckhauser, who did work for Sabino and other contemporaries of Lalique. Most of the finer glass of this period was done by the French but the English firm of James J. Jobling also created some innovative designs after having earlier sought to sign distribution deals with some of the major French factories. Today, few glassmakers still make opalescent glass primarily due to the toxicity of the chemicals needed to execute the complex glassmaking process making pieces found in shops and flea markets all the more a treasure.
Moore, Ed.D., is a specialist in the valuation of antique and collectable objects of the last 100 years. He is an educator, counselor, and avid antique enthusiast. He has been a collector of antique American Art Pottery and has been a dealer for over 20 years. He is familiar with nearly all lines of American Art Pottery, twentieth century glassware, Art Deco, and Art Nouveau categories. If you have a question about antiques or collectibles, you can e-mail him at buddm4cnsl@comcast.net, An answer to your question may appear in a subsequent column.