Sea Glass Insulators: Intriguing, Illustrious Finds

The History surrounding Sea Glass Insulators: Intriguing, Illustrious Finds
By Ellie Mercier, member North American Sea Glass Association

Discovering remnants of historical significance is certainly one of the most fascinating thrills of the hunt, and uncovering finds boasting the romantic charm of those derived from the bygone era of insulators is no exception.

Blue insulator
Blue insulator

The desirable attributes of insulators are not limited to beauty and nostalgic appeal, but the invention of these sought after collectibles was integral to the advancement of technology. During the nineteenth century, hopes for a promising future following the discovery of the telegraph began to fade when it became apparent that society lacked a viable means to transport electricity. However, attributed to the debut of the insulator in 1844, public faith in the innovative technology was soon restored. Originally produced from glass, in a variety of shapes, colors and sizes, insulators were installed on telegraph lines (and eventually, on telephone and power lines) to separate the wires from the tall wooden poles used to secure the lines in the air. Their purpose was to keep the wires isolated to allow electricity to pass through without interference. As technology progressed, particularly as the railroad expanded and electricity was required to operate train signals at stations throughout the nation, the demand for insulators skyrocketed, and hundreds of millions were manufactured between 1875 and 1930.

aqua insulator - a common color
aqua insulator – a common color

Alike bottles (and sea glass remnants), the majority of insulators were either colorless (clear) or produced in the shade of aqua (due to the fact that glass possesses a green tint in its natural state); however, glass insulators were fabricated in many other colors as well, including amber, cobalt, darker greens, and purple. Around the turn of the century, the onset of higher-voltage electric wires prompted a demand for ceramic insulators, of which offered more protection for wires than their glass counterparts. Ceramic insulators were also manufactured in multiple hues, ranging from yellows and greens to blues and browns. In addition, factories tested insulators of various shapes and sizes to develop models that would efficiently hold the electrical wires in place and ensure the wires remained insulated.

After an entire century of active production, the demand for insulators significantly declined as utility and electric companies began to install wires underground, and by the 1960’s, it was common to observe retired insulators, in an array of colors and styles, strewn on the ground in the vicinity of railroad tracks and construction sites. Not surprisingly, individuals began to seek out the charming, but no longer practical objects, prompting a flurry of passion for insulators that would ultimately inspire a generation of collectors and continue into the twenty-first century. In fact, the 1960’s onset of  “insulator fever” was so intense that by the end of the decade, pioneers of the hobby had founded The Crown Jewels of the Wire, the first national insulator magazine, and another major milestone transpired in 1973, with the establishment of the National Insulator Association.

Blue insulator sea glass - photo by Lisa Crabtree
Blue insulator sea glass –
photo credit Lisa Crabtree


As enthusiasm for the hobby continued into the 1990’s, the value of insulators skyrocketed, and it wasn’t unusual for rare specimens to fetch thousands of dollars at auction houses. For the most part, insulators manufactured between 1885 and 1960 are considered collectible, yet those produced prior to the turn of the century are the most desirable. Generally, collectors determine the values of insulators based on the same characteristics used to rate sea glass and bottle finds, including color, shape, condition, and the presence of, or lack of embossing. Since they were produced in 460 shapes, 2800 different embossing patterns, and almost 9000 color combinations, it often takes time to become familiar with the multiple varieties of insulators. Therefore, insulator price guides are an extremely helpful resource for novice and experienced collectors alike. The guides are not only ideal for identifying manufacturer marks and style numbers commonly embossed on insulators, yet they feature sections dedicated to topics such as foreign produced insulators, the countless styles of insulators (IE: pin type and non-pin type), and favored collectibles, including the beloved ‘Mickey Mouse” shape and highly prized examples comprised of carnival glass.

Insulator sea glass - photo by Lisa Crabtree
Insulator sea glass – photo by Lisa Crabtree

Today, support for the pastime remains strong, as reflected by the numerous clubs and shows that exist around the globe in celebration of the vintage beauties. In addition, hobbyists have access to dozens of insulator-related websites. Two particularly notable online presences include, hosted by the National Insulator Association, and, a site referred to as “Insulator Collectors on the Net,” which has a following of 1500 members.

In addition to history buffs and railroad enthusiasts, it’s common to encounter sea glass and bottle collectors at insulator shows due to the fact that the pastimes share a direct connection to the history of glass manufacturing and the timeline of bottle production. Whether admiring a lustrous insulator made from carnival glass or discovering the smoothly tumbled remains of a cobalt insulator ashore, the experience is bound to arouse nostalgia for the romantic charm of an earlier