Made of Recycled Glass Planet Earth Art! Wear the Earth around your neck with this lovely transparent blue art glass marble necklace! Geographically accurate natural continents in amazing detail, including rivers, forests, icecaps and deserts. This geography lover's necklace was made in the USA from recycled glass. Great gift for a world traveler or someone who would love to travel the world. Make Every Day an Earth Day! Marble measures approximately .9 inch (22 mm) diameter. Leather Corded.