Green Enamel and Crystal Shamrock Stud Earrings. In ancient times, a tiny three-leaved plant bloomed far and wide and laid a carpet of green all over the limestone hills of Ireland. The druids knew the Shamrock has mystical powers. To them its three leaves were a natural sign of a sacred number. This little plant was even said to warn of an approaching storm by turning up its leaves. According to legend St. Patrick himself plucked a Shamrock from the ground to explain his belief in the Holy Trinity. They say this helped convert the Irish people to Christianity. Many believed that wearing this little sprig of green would keep them from harm.