Until the 1960s, it was common for some companies and turists in coastal towns to dispose of empty glass in the water. These broke aparts during flouncing and the sharp shards (commonly triangular shaped) were smoothed roundish by water, sand and rocks. Glass have a frosted patina, because of corrosive effect of salty water. This process takes about 20 years. Sea glass can be found almost in every color of the rainbow, but turquoise, brown, green and white (clear) are the most common. They are perfect decorating elements for a waterside theme interior.