Dating purple glass
The normal colour of uranium glass ranges from yellow to green depending on the oxidation state and concentration of the metal ions, although this may be altered by the addition of other elements as glass colorants.Uranium glass also fluoresces bright green under ultraviolet light and can register above background radiation on a sufficiently sensitive Geiger counter, although most pieces of uranium glass are considered to be harmless and only negligibly radioactive.Carnival Glass, first produced about 1908, and extremely popular throughout the 1920s, (and again in the 1970s) is merely a general term which means glass that has been “carnivalized”, that is, has an iridescent multi-colored “rainbow sheen” or “gasoline on water puddle” appearance, produced by spraying metallic salts on the glass surface during manufacture.For more information on Carnival Glass, check out this great site: David Doty’s Carnival Glass website ).Some Depression pieces are hard to classify as to the exact pattern name, or might be called “generic” pieces, such as some rather plain-looking sugar bowls, salt shakers, ashtrays or other items that don’t seem to match any photos in depression glass price guidebooks.Although much of this type of glass is of low to medium quality (for instance, because of molding flaws), Depression glass has been highly collectible since the 1960s, but with the market fluctuating somewhat……and down in cycles……the last several decades.“Depression glass” is a term that is sometimes bandied about indiscriminately by glass collectors, and sometimes incorrectly.Basically, this is a catch-all phrase for a general type of inexpensive glassware, in clear or colors, that was sold (or given away as premiums) during the late 1920s into the early 1940s.
Some of the most common pieces in a plentiful pattern may sell for only a few dollars, but rare pieces in certain patterns can sell for hundreds of dollars at depression glass shows.
Vaseline glass is now used as a synonym for any uranium glass, especially in the United States, but this usage is not universal.
The term is sometimes carelessly applied to other types of glass based on certain aspects of their superficial appearance in normal light, regardless of actual uranium content which requires a blacklight test to verify the characteristic green fluorescence.
Most such objects are now considered antiques or retro-era collectibles, although there has been a minor revival in art glassware.
Otherwise, modern uranium glass is now mainly limited to small objects like beads or marbles as scientific or decorative novelties.As far as reference books, often available at local libraries or at bookstores, as well as available for purchase online, every serious collector of Depression Glass would greatly benefit from obtaining and studying copies of “” (1974), written by noted collector, author and researcher Hazel Marie Weatherman.The books have been widely reprinted since the 1970s, and are chock full of great background information and photos– describing many patterns and pieces, and including reprints of various glass catalog pages, info on glass companies of that era, etc.In the United Kingdom and Australia, the term vaseline glass can be used to refer to any type of translucent glass.