Sea glass or beach glass can be found among some of the garbage that gets washed up on shore. Beach glass is broken pieces of glass that have been worn down by constant erosion for months or years until they look like rough gemstones. Green, brown, and clear glass is the most common. These are from beer and wine bottles as well as food and medicine jars. Broken pieces of tile, pottery and ceramics with their broken edges evenly smoothed out by constant erosion can also be found.
Different shades of blue glass are more difficult to find. The darkest shades of blue come from Noxzema and Vick's VapoRub jars. These products now come in plastic containers which will make the color tougher to find in years to come. Medium shades of blue glass or aqua come from mason jars and apothecary jars. The lightest shade of blue or bluegreen glass comes from the old Coca-Cola bottles which have also been replaced with plastic.
The rarest color to find is red. This was used for car taillights, old highway sign reflectors, and boat sidelights. Rarer still is pieces of Depression Glass which comes in many colors. The most common being pink, yellow and lighter shades of blue and green. There is a story behind every piece of glass and where it comes from.
My wife has a cube shaped jar filled with beach glass on her desk. The different shades of blue and green remind her of the beach. An artist friend makes concrete pads for garden walkways. He embeds beach glass, broken tile and other objects for decoration. You can make jewelry or use it like any other craft material. No two pieces are alike and best of all it's free.