Silvertone Horizontal Year 2021 Green Shamrock Necklace and Clover Earrings Jewelry Set. Silvertone Horizontal Year 2021 is approximately 0.37 x 0.56 x 0.05 inches (HxWxD) including loop. Great graduation gift. Silver tone faceted ball chain necklace is 18 inches long with a spring ring clasp. Green Crystal Post Earrings have a steel post and a plastic comfort ear nut. Sweet green Irish Shamrock is hand painted enamel and is a famous symbol of Ireland and St. Patrick s Day. The symbol was used be St. Patrick to spread Christianity as a symbol of the Holy Trinity.