Walking on the beach, it’s not uncommon to notice vibrant fragments of weathered glass nestled amidst the grains of sand. What you’re seeing are remnants of what was once discarded refuse.
In my role as an environmental science lecturer, the ocean’s offerings like these pique my curiosity. I’ve examined sands worldwide, incorporating specimens such as sea glass into the environmental and geophysical collections at UMass Lowell.
These marine deposits, once trash, now treasures, highlight the nexus of human behaviors with the Earth’s organic rhythms.
Before the surge of disposable plastics in the early 1970s, glass was the favored packaging material. Ancient civilizations like the Egyptians, Greeks, and Romans employed glass for myriad purposes, including windows and containers.
Come the mid-20th century, households in America received milk in glass bottles, and carbonated drinks also came in glass. Once their use was over, they were often discarded in landfills.
The environmental awareness of the 1960s wasn’t prevalent earlier, and dumps in America were typically exposed, and vulnerable to the elements. Many were located near water sources, and rain would carry trash, including unwanted glass items, into the sea.
Journeying towards the sea, glass containers would collide with rocks and debris, fragmenting them. Once these shards reached coastal regions, tidal forces carried them into the oceanic depths.
The ocean’s wave dynamics grind these shards against sandy beds, refining their jagged contours and bestowing upon them a distinctive matte and pockmarked texture.
All glass originates from sand, primarily quartz sand. This transparent or white sand is evident on several Florida Gulf Coast beaches.
To transform sand into glass, it’s purified to retain only quartz, then melted down. Additives like soda ash and limestone enhance its ductility and durability. This is then shaped into various products.
Given that quartz is the foundational element of glass, several of its properties manifest in sea glass. Its near transparency is evident, but also its distinctive fracture pattern.
Quartz breaks in a specific way, known as a conchoidal fracture. This breakage radiates from a singular point in a crescent fashion, reminiscent of seashell interiors.
Furthermore, quartz’s resistance to chemical erosion is noteworthy. Consequently, sea glass fragments over time but doesn’t degrade swiftly.
Sea glass undergoes years, sometimes centuries, of oceanic tumbling, refining its edges. Quartz’s resilience ensures that these fragments endure in nature for extended periods.
The commerce around sea glass in the U.S. is booming, endorsed by entities like the North American Sea Glass Association and its international counterpart.
Craft fairs nationwide display sea glass artifacts. Nearly every coastal town in America probably has a local artisan fashioning unique sea glass creations.
However, with plastics replacing glass in many applications, genuine sea glass might become rarer. The shift in usage means more plastic and less glass entering our ecosystems.
Given the declining availability of authentic sea glass, some merchants produce imitation sea glass using mechanical and chemical processes. Although similar, genuine sea glass possesses irregular pitting, unlike its manufactured counterpart.
Public sentiment might eventually pivot from disposable products back to glass. Glass can undergo numerous recycling cycles without degrading, and its environmental toll is less than that of microplastics.
Yet, given the lack of a broad market for recycled glass and its cumbersome nature, recycling it isn’t always economically viable.
However, there’s a growing call for eco-friendly substitutes to disposable plastics. Aluminum containers are gaining traction, and glass remains a viable alternative.
If not responsibly recycled, the glass discarded today will become the sea glass treasures for future beachcombers.
