Tulsi is thought to be the most sacred of woods in India and Indian worship, and the plant of Tulsi is believed to be the incarnation of the Divine itself. The Tulsi Mala is made of the wood or the seeds of Tulsi and is used for name chanting and worship.
It is said in Vishnudharmottar : The Lord says that one who wears the beads made out of the wood of Tulsi in one’s neck, even if he is untidy and ill- charactered, will undoubtedly attain Me only.
In Kaliyuga, one, who is bedecked with the beads made of Tulsi, performs ritual activities and activities pertaining to ancestors and demigods, obtains crores times more results. The messengers of Yama will flee away by the sight of the Tulsi beads just as leaves are blown off by wind.
Moreover, the Tulsi Mala is said to have incredible spiritual and physical healing powers apart from helping the mind to focus during prayers.
The Tulsi Mala is made of Tulsi wood and consists of 108 beads wound around a strong string, with a 109th bead called the Sumeru bead of some other material like a metal or crystal, or a bigger Tulsi bead itself. One starts counting the beads from the bead adjacent to the Sumeru bead of the Tulsi Mala and completes one full round. On second round the Tulsi Mala needs to be counted in the reverse direction again as the Sumeru bead should not be crossed while praying. Depending on the type of the Tulsi plant, the Tulsi Mala is available in various colors like black, brown or sandalwood colour.
Tulasi beads are said to protect one from bad dreams, accidents, attack by weapons, and inauspicious destinations at death. For these reasons and because she is dear to Krishna, devotees always wear Tulasi.
. The benefits of the leaves of Tulsi is well proven, and owing to its spiritual and physical healing powers, the touch of the Tulsi wood acts as a rejuvenator for the stressed mind and brings the spiritual self of a person closer to God. On top of that, wearing the Tulsi Mala is supposed to bring good luck and fortune to the devoted wearer. It is said to balance the kapha and the vata dosha. Tulsi clears the aura, and its subtle smell fills the heart with sensation of the divine.
Reference : http://blog.srisankaratv.com/2018/03/15/significance-and-benefits-of-wearing-tulsi-beads-around-the-neck/