The Sea Glass Shard of the Month: June 2015
Privacy Window Sea Glass
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Sea Glass Specifications:
Color: White (Frosted Clear)
Max Length: 46.0 mm (1.81")
Max Width: 23.9 mm (0.94")
Max Thickness: 3.8 mm (0.15")
Weight: 6.7 grams (0.24 oz)
Estimated Age: 50 to 100 years old
Following up last month's article on pressed glass we'll take a look at a specific type of pressed glass often used in windows and doors. This month's feature is a shard from Puerto Rico that has a pattern embossed on one side while the other side remains smooth. This type of glass is referred to as privacy or obscure glass because the embossing diffuses detail from the other side while still allowing light to pass through. The amount of diffusion depends on the type of texture embossed in the glass.
Facts of Interest
The Romans were the first known to use glass for windows, a technology likely first produced in Roman Egypt—in Alexandria around 100 AD–although it had poor optical properties. [1]
Obscure glass was used in doors, above doors and windows built in the interior as well as exterior of a building where some amount of privacy was desired while still maintaining lighted conditions.
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...the embossing diffuses detail from the other side while still allowing light to pass through. |
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Patterned windowpanes have been manufactured at least as far back as the late Victorian times and come in many designs including a pebble, wavy, ribbed and flower texture. The manufacturing process used to create this type of textured windowpane, called rolled plate glass, was first developed by the Chance Brothers in the 1880s. This process required rolling the plate glass while still in a plastic state between two rollers with one containing the pattern although sometimes both had a pattern.
The type of pattern shown in this month's shard is termed Florentine by professionals in the windowpane industry—referred to as a flower or snowflake texture by the layperson. On eBay, many listings for Florentine windowpanes reveal glass that has been salvaged from Victorian homes therefore it is assumed this style has been produced as far back as the late 19th century. Reproductions of this pattern, along with other styles and colors, are sold today as replacement panes.
While privacy sea glass can be collected almost anywhere there appears to be a lot of this textured glass being collected in Puerto Rico. The age of such glass can be difficult to estimate because reproductions, as mentioned earlier, are still being manufactured today in various colors. With that said, if you do happen to find a piece of privacy sea glass that is sun-colored amethyst it can be assumed that it came from the window or door of an old Victorian home.
REFERENCES:
1. http://en.wikipedia.org/wiki/Window
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