PIRATE GLASS: Castaways WORTH SAVING

Beach and lake glass, sometimes called "mermaid's tears," make wonderful souvenirs not only for the naturally tumbled beauty of such pieces but also for the stories they can tell.

- L.A. SOKOLOWSKI

For instance, the Finger Lakes region of central New York is known as "wine country" but one of its unexpected collectibles is the lake beach glass, sometimes still faintly bearing the etched lettering of its origin story, found with particular prevalence along the eastern side of Seneca Lake at Lodi Point Beach State Park.

Why? Old wine bottles: Castaways of vineyards past.

But rarer still are the ancient maritime castaways of ale and rum bottles from the Golden Age of Piracy (1650-1730), known as "pirate glass," that wash up on the beaches along the Caribbean, North American eastern seaboard, West African, and Indian Ocean shipping lanes and trading ports.

Such Shanghai surprises tantalize collectors but not every dark piece tells the same story. Because, as Captain Jack Sparrow liked to say, "Not all treasure's silver and gold, mate."

THE DARK SIDE

Pirate glass is colloquially described as "black" but the intensity of what is more likely to be blue, brown, green, purple or red glass has been deepened by the addition of cobalt, copper or iron oxides; or during the glass-making process, the addition of iron slag, or coal and wood ash.

Why darken glass? To extend the life of products and their transport because darker glass protects valuable liquids (like alcohol or oil) from degeneration by sunlight.

The same properties added to deepen color also improve the structural integrity of the glass and make it less likely to break during handling and storage.

At sea, water may turn too contaminated to drink, but not ale or rum. Or a seafaring elixir of lime, sugar and rum often kept aboard in dark bottles as a survivalist measure against scurvy.