Sea glass

In this process, the glass loses its slick surface but gains a frosted appearance over many years.

[3] The most common colors of sea glass are kelly green, brown, white, and clear that come predominantly from bottles of beer, juices and soft drinks and fishing floats.

[5] Extremely rare colors include gray, pink (often from Great Depression-era plates), teal (often from Mateus wine bottles), black (older, very dark olive green glass), yellow (often from 1930s Vaseline containers), turquoise (from tableware and art glass), red (often from old Schlitz bottles,[6] car tail lights, dinnerware, or nautical lights, it is found once in about every 5,000 pieces), and orange (the least common type of sea glass, found once in about 10,000 pieces).

Some shards of black glass are quite old, originating from thick eighteenth-century gin, beer, and wine bottles.

[5] Old black glass bottles that had iron slag added during production to increase strength[7] and opaqueness were at times broken in shipment.

[10] An example of natural sea glass will usually have a frosty, almost powdery texture at different points.