Sea Glass Pastels
Tell-tales from the Past
By Richard Lamotte
During the late 1800s, a Second Industrial Revolution, also known as the Technological Revolution, was in full swing, and demand for glass containers was skyrocketing. Bottles and jars from this period are the primary sources of the pastel-colored shards favored today by sea glass collectors. Back then, beverage, food, and medicine companies were aggressively marketing their new products to wider audiences. City life was flourishing, and freshly completed railroads could carry people and goods across the United States. As a result of an escalating demand for glass containers, production techniques in the late 1800s focused more on maximizing output instead of attention to unique design details. Bottles were often made with thicker walls, at times ¼ inch, not only for safe hauling but because many buyers hoped to get abundant local reuses from a bottle filled and later refilled by the seller.
This manufacturing boom from 1880 to 1920 meant that natural metal elements found within the silica, which is the primary ingredient of production glass, created a common palette of bottle colors during that era. Most semi-transparent containers were created in a soft blue, due to traces of copper oxides, or a soft green, due to iron oxide impurities. Some remnants of clear bottles also made in that period appear today as soft purple, due to the effects of sunlight on one of its components, manganese. Many glass containers also had a few stray bubbles, as most were hand blown until very late in the 19th century.
Even today, many collectors still identify thick Coca-Cola bottle shards by their unique “hobble-skirt” or ribbed design. But if that soft green shard does not have the familiar ribs or Coca-Cola logo, then it is very likely at least 100 years old. When Coca-Cola began using their trademark bottle (designed by Root Glass) in 1916, many other bottlers were already working with clear glass. Coca-Cola was one of the only large bottlers to stay with that green color and style for over 50 years before transitioning to clear in the 1960s.
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The ubiquitous pastel blue bottle has a bit broader range of history since it became popular for mineral waters and beers by the late 1860s. By 1900, translucent blue was already a mainstay beverage and patent medicine container color yet soon would be surpassed by clear glass around 1920. Soft blue, however, continued its run as a common canning jar color well into the 1930s. Later, several popular sodas like Pepsi would use soft blue in their vessels, but by the 1950s, far fewer mass-produced bottles came in any translucent blue tint.
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In addition to the pastel blue and green bottles copiously produced at the turn of the 20th century, a rapidly growing number of virtually clear bottles were being created with manganese, which was intentionally added to decolorize the glass. The goal, of course, was to see the true contents inside the bottle. The only problem was that the manganese oxide within the glass could slowly oxidize over time and develop a faint lavender color when exposed to sunlight. The use of manganese to decolorize glass gained popularity in the late 1870s, but most manufacturers began switching to selenium or arsenic by 1915. Manganese was no longer used in bottle production by 1920. One reason is that U.S. glass producers had trouble obtaining manganese from African mines controlled by the Germans around the First World War. Other sources state that manganese was less desirable for use in the new Owens’ automated bottle machines that took over the industry by 1920. As a result, by 1916, many domestic producers of clear glass began using selenium to decolorize bottles. However, once again, after prolonged exposure to sunlight, those vessels with selenium would slowly discolor, this time to a pale straw yellow or faint beige.
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End of an era
Finally, when glass bottle makers began using arsenic, they were able to produce clear glass that maintained its colorless state. It was during that same period the Owens’ fully automated bottle machine (ABM) became the industry standard. Introduced in 1905, it used the still common “Crown Cork Seal” which, in turn, became a global lip design by the 1920s. Colorless glass began to take over, and the four decade proliferation of pastel vessels soon vanished. These were only later to be found at bottle shows, in antique stores, and as cherished remnants on our beaches. When automation arrived, bottle walls got thinner, color preferences compressed into clear, green, or brown, and most bottles had a Crown Cork Seal or screw-top closure. Creative designs became far less important to the bottle industry than output and shipping costs.
The truly natural colors of the past began vanishing, and they continue to disappear with each rising tide. Look at your sea glass collection and treasure those pastels.
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This article appeared in the Glassing Magazine September 2017 issue.
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Bottle neck image ©2015 Celia Pearson, The Lure of Sea Glass
Shell and pastel sea glass image ©2017 Tommy Allen, Pure Sea Glass 2018 Wall Calendar