Humans have broken and thrown away much glass throughout history. Unlike plastic, glass is created from sand and eventually erodes back into sand. Before it becomes sand, the ocean tumbles it into “sea glass” Sea glass beaches can be found in the northeastern U.S.
The ocean’s tides roll and tumble glass shards over decades, smoothing and rounding the edges. The glass becomes frosted. 30-100 years pass. Color can tell sea glass collectors where and when it was made. The most marine glass comes from modern beer, juice, soft drink bottles, plates, drinking glasses, windshields, and windows.
Less common colors include jade, amber, forest green, ice blue from 19th- and 20th-century whiskey, medicine, ink bottles, and 1960s soda bottle lime green. One in 25 to 100 sea glass pieces is this color. Purple, cobalt blue (from early Milk of Magnesia, poison, and Vicks VapoRub bottles), and aqua are less prevalent (from Ball Mason jars). One in 200 to 1,000 pieces has these hues. Gray, pink (from Great Depression-era plates), teal (Mateus wine bottles), yellow (1930s Vaseline containers), turquoise (tableware and art glass), red (vehicle tail lights and nautical lights) and orange are rare. 1,000 to 10,000 pieces are these colors. Even rarer is 500-year-old black glass from Caribbean pirate booze bottles.