Sea glass offers rewards distinct from other collector's items, as its colorful shards accrue ever more value as they're smoothed over by the natural world. Once found and classified, the beautiful pieces -- derived from bottles, tableware, and other objects -- connect us with the fascinating history of glass around the world.

Sea glass is formed as discarded shards tumble along the shore, slowly forming round stone shapes. As the surface of the glass absorbs moisture, soda and lime components are leached out. This leaves a variable pitted surface, which refracts light and retains minerals on its surface.

How to Gather Sea Glass
Richard Lamotte, a sea-glass collector and author of "Pure Sea Glass," shares gathering tips.

When to Look
People tend to hunt for sea glass on beaches during the summer months, but that's not the best time to find it. "Fall and winter months normally outshine summer collecting because winds and tide changes are stronger and aggressively batter the shorelines," Richard says. In addition, full moons create more extreme tidal patterns, leaving more sea glass exposed on beaches.

Where to Look
River mouths that open into large bays or oceans, as well as stone beds near jetties, are great places to gather sea glass. It helps to do a little historical research. "Since most shards don't travel far from where they were deposited, talk to local historians and find out what beaches and ports were most popular around 1900," Richard says.

Richard Lamotte's Sea Glass Collection
As one of the world's foremost sea-glass collectors, Richard has amassed an impressive collection of rare pieces. He shares examples from three categories of rareness.

Extremely Rare

• Orange: The rarest of all sea-glass colors, orange glass was only produced for a small number of Art Deco tableware pieces. Richard's glass appears to be the handle from a serving piece.
• Red: Most red sea glass comes from tableware and warning lights. Richard's piece derives from a bottle made for Schlitz during the fifties.
• Yellow: Very few bottles were ever made in yellow. Most of the yellow sea glass that exists comes from tableware.
• Black: Often dating back to the 1700s, black sea glass is rare in many areas of the United States but relatively common in parts of the Caribbean.

Rare

• Cobalt: One of the most popular sea glass colors, cobalt was mostly used for medical purposes during the early 20th century. A primary producer was Maryland Glass, which created the Bromo-Seltzer bottle from which Richard's piece derives.
• Purple: These pieces began as clear glass, made with manganese. The element oxidizes to purple after years in the sun.
• Aqua: Sources of aqua sea glass include insulators and Ball mason jars from the early 1900s.

Uncommon

• Soft blue: The majority of bottles made in the early 20th century were soft blue, as were windows and windshields. Especially prized among collectors are the soft blue bottle stoppers manufactured around the turn of the century.

Resources
For more information about sea glass, visit pureseaglass.com.