What is Sea Glass / Beach Glass?
“Sea Glass” is the general term used by beachcombers and collectors for pieces of weathered glass found along the shores of large bodies of water, including seas, oceans, large lakes, etc. The term “Beach Glass” is more or less synonymous with “Sea Glass”, but is more commonly used for glass found along inland rivers and other bodies of water where wave action is generally less intense, and as a result, the glass is not usually worn down as heavily.
Sea glass gradually acquires a frosted “matte” look by exposure not only to long-continued surf action (numerous microscopic scratches caused by repeated abrasion by gravel and sand particles), but additionally perhaps in some small measure by contact with the saline (salty) environment of ocean water.
Sea glass tends to be more smoothly worn, more rounded and pebble-like, with less markings still legible on individual pieces. Beach glass (from shores of inland rivers and lakes) is typically less worn, often with embossed/raised markings that remain clear enough to help identify what type of item (bottle, jar, insulator, tumbler, plate, window pane, etc) the glass was originally part of.
The most common colors of sea glass include clear (“flint” or “white”, used for innumerable common bottles and jars of every description, especially made within the last 70-100 years, window glass, tableware, etc), emerald or lime green (typical of older Sprite, 7-up, gingerale and other soda bottles), and shades of amber (including medium brown or “beer bottle brown” glass.)
Less common are various shades of aqua (light blue-green), which was the typical color of a good percentage of common bottles and jars made (in general) before the 1920s. Many older electrical insulators were made in some shade of aqua glass, ranging in depth from a very pale, “washed out” aqua to an intense dark “teal” aqua or dark green. Along Pacific Coast beaches, some aqua sea glass could theoretically result from broken glass fishing net floats.
Other colors, less frequently found, include amethyst (very light to medium purple indicating the presence of manganese used as a decolorizer, very common in bottles from the 1890-1920 period), cobalt blue (Bromo-Seltzer bottles, Milk of Magnesia bottles, Vicks Vaporub jars, many other products), forest green, sapphire blue, light blue, cornflower blue, olive green (Champagne and many other types of bottles), olive amber, kelly green, dark purple, light green and pink (Depression-era glassware), medium/dark turquoise or dark teal green (stoplight lenses for the “green light”), teal blue, light yellow or yellow amber (as used in Depression era glass tableware); blackglass (intense olive green or olive amber typically used for some beer, ale, bitters and whiskey bottles pre-1890); white milkglass (salve, cosmetic & cold cream jars, bud vases, decorative tableware, and much more), gray (perhaps television faceplates or other tech/industrial glass products, some thick plate glass), purple blackglass, true yellow, ruby red (vehicle taillight lenses, stop light lenses, railroad light lenses, upscale tableware, etc), and true orange, which is very rarely found. Occasionally, opaque colors are found, including purple slag (marbled white milk and opaque purple), green (“Jadite”) and other colors. A specific color may be called by different names by different persons, including some of the colors within the preceding list!!
It is often difficult to ascertain what any particular piece of sea glass came from, which adds to the mystery and fun of collecting. Many colors found in “old” glass are also being made in new items (such as various shades of green, olive amber and aqua that are used for certain types of present-day wine or bottled water bottles) so color alone may not help identify an age range for any particular piece of glass. In general, older bottles were made of heavier and thicker glass than present-day bottles. This is especially true of old soda and beer bottles. The presence of many bubbles is usually (but not always!) an indication of some age, as most glass before c. 1920 tends to have more bubbles in it than modern glass. In the case of modern “art glass” and other decorative glass, however, bubbles are often intentionally left in it for an attractive effect.
There are a multitude of minor color shades that are difficult to define. There are many shades of “off-clear” tending to lean, for instance, toward peach, straw, gray, green, blue, lavendar and other color directions. “Clear” bottle glass with a faint straw, peach or yellowish tinge was common in the 1910s-1940s as a result of the element selenium being added to the batch as a decolorizer.
Although virtually any type of glass object might eventually wind up as a piece of sea glass or beach glass, a large percentage of this glass originates from containers thrown away in the trash. A good percentage of these containers have washed into rivers (and ultimately, oceans and lakes) along with driftwood, plastic and other debris after rises in water levels as a result of heavy rains and/or melting snows. Virtually every river carries floating debris after a marked rise, and oftentimes the bottles and other glass containers afloat on these bodies of water are carried along for hundreds of miles from their original source of deposition in headwaters (minor tributaries, streams and creeks located far inland) before they are eventually carried out to sea, and ultimately wash ashore. Winds and waves, combined with abrasion on rocky, gravel or sandy beaches starts the process of breaking up the bottles and they eventually wind up as “sea glass”. Sometimes bottles are smashed into pieces by mischievous children (and adults) playing along sea shores, and then the pieces are further weathered by wave action.
Some unknown percentage of sea glass originates from bottles thrown overboard from ships and boats, although I believe that is actually a rather small percentage, and in fact the majority of bottles cast up onto beaches (either ocean, estuary, sea or river beaches) come from trash washed from inland sources. It can also depend on the exact locality where the glass is found; the location and proximity of nearby rivers and their outflow currents; whether or not a beach is near a major shipping lane; how popular a particular beach is (with tourists, who might leave trash behind such as wine bottles); the frequency of strong oceanic storms in a particular area, and many other factors.
Sea glass /Beach glass that originates from “non-enclosed” (not floatable) glass objects may come from trash that was disposed of relatively close to the actual place where it is eventually found. (Any bottle that has floated for long distances would have had the lid intact and tightly closed, otherwise it would have filled with water and sunk). Some areas along shorelines and beaches were once “unofficial” dumping areas, landfills or trash dumps, later to be uncovered by shifting beach erosion zones. In these cases it is not that unusual to find, along with beach glass, worn sherds of pottery bowls and crocks, pieces of ceramic/china dishware, old porcelain doorknobs, small “spool type” porcelain home wiring insulators, and other durable (“non perishable”) related artifacts, remnants of typical household and/or construction-related trash.
Sea glass is collected for it’s interesting colors and textures, for use as part of craft projects, for incorporating into jewelry, mosaics, art projects, etc. Sometimes collections are displayed in clear glass jars, bottles, fishbowls, brandy snifters or vases, with the glass grouped by single colors, or with a number of different colors mixed together.
Sometimes the glass is picked up by a casual beachcomber purely out of curiosity at to where it came from, or what a piece might have originally been part of, and eventually this interest expands into a full-fledged hobby.
NOTE: Alot of the so-called “sea glass” sold on the internet is not “as found”, but was “artificially created” by using a rock tumbler or similar means. Fake sea glass is frequently sold on sites such as ebay, so proceed with caution if you are buying it online. The authentic product is very difficult to fake, and fake sea glass can usually be differentiated from authentic, natural sea glass, but only upon close inspection.
Much more information can be found at the North American Sea Glass Association website here: http://www.seaglassassociation.org.
For an extensive list of marks and symbols that might be seen on pieces of beach glass (some with accompanying illustrations), please check out my “Glass Bottle Marks” pages….. Page one starts here.
This webpage is currently under construction. More pictures to be added later. Thanks for stopping by!!