Best place to find it:
Playa Cofi, on the north shore of Vieques, a 30-minute flight from San Juan, Puerto Rico. The beach is sprinkled with colorful bits of bottles and jars frosted smooth by fine sand and wave action. (Hatteras Island, North Carolina, and Hammonassett Beach State Park in Madison, Connecticut, are other good bets.)
Why here: High tide washes ashore broken bottles, jars, and dishware from nearby shipwrecks and old landfills. There’s nothing like finding rare bits of red glass from old cars!
Don’t miss: The Beading Bikini, which sells handmade sea glass jewelry; 787/435-6850 or beadingbikini.com.