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ANSWER: Ever since it’s inception, the term stretch(not stretched) has confused people. It appears mistakenly on price tags in antique shops and in online descriptions. Because of the word “stretch,” People imagine a piece from the 1950s or 1960s that has been stretched to make it taller or wider, but stretch glass is entirely different.
Some people believe stretch glass is swung back and forth on a rod to make it stretch outward. Or, they think it looks like a strange type of Carnival or art glass, so it must be that. Neither is correct. Most of the time, people's first reaction is how beautiful the glass is, but they don't know anything about it.
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Created by several American glass factories from 1916 to the early 1930s, iridescent stretch glass is a pressed or blown molded glass. It’s shaped and formed—pressed or blown into molds—reheated and then sprayed with a metallic salt or dope, a procedure called doping, while the piece is still hot. The glass blower then reheats the piece and this is when the stretch marks occur. The glass expands faster where the dope blower applied the dope, which causes a crackled, web-like appearance on the glass. Further shaping emphasizes these stretch marks. Some blowers often shape or "work" the glass a lot which emphasizes the stretch marks in the iridescence while others don’t work their pieces as much, resulting in finer stretch marks and are only satiny.
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People also confuse freeform art glass, produced from the 1950s to the present and commonly posted on eBay, with stretch glass.
Companies that produced stretch glass included Central Glass Works of Wheeling, West Virginia, Diamond Glass-Ware Company of Indiana, Pennsylvania, Jeanette Glass Company of Jeanette, Pennsylvania, Vineland Flint of Vineland, New Jersy, and United States Glass Company of Pittsburgh, Pennsylvania.
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The most common stretch glass color that can be found is celeste blue, as well as the topaz and pink. Blue was the dominant color though, along with topaz, both of which were good selling items when they first appeared. Topaz was a good seller in the 1910s and 1920s because not everyone had electricity. This color catches the light and reflects it very well. There’s also a lot of Florentine green stretch glass out there as well and crystal stretch glass, which has a frosty white iridescence. With so many stretch colors out there including aquamarine, blue smoke, coral, custard, pink and white luster, beginning collectors are sure to find a favorite of their own.
Iridescent stretch glass not only comes in a variety of colors, but also a range of prices. Pieces that once sold for 25 cents to $1 can now be picked for $25 to $50, and even $10 to $15 for more common pieces.
High-end pieces, such as a Fenton No. 604 punch on a red stand, can sell into the thousands. One sold on eBay for $4,200. While the price may seem high, anyone can acquire a decent collection of stretch glass if they buy pieces in the $25 to $100 range.