Conjuring up images of crystal blue waters and seaside serenity, Aquamarine has long been associated with the calmness and tranquility of clear blue skies and oceans. March's mood-enhancing birthstone was once believed to have come from the treasure chests of mermaids, leading to its popularity as a protective stone for the safe passage of sailors and other travelers. The aquamarine is also the traditional gemstone given on a 19th wedding anniversary.