One of the most common things that one can spot in the neck or hands of a person who follows the Vaishnava tradition is the Tulsi mala. It is a sacred garland from the Tulsi plant, the roots, leaves, twigs, and more, and is worn either around the neck or used as a rosary to do chantings.
In Hindu tradition, Tulsi is not just a plant but a Goddess who ensures peace, prosperity, good health, and more in the lives of the people who nourish her.