If your tulsi mala turns black it may be a sign of improper care or prolonged exposure to external factors. Tulsi malas are traditionally used for prayer and meditation, and their blackening can result from regular use humidity, or even contact with oils and sweat. To prevent this, keep the mala clean and dry and avoid wearing it while sweating or during excessive physical activities.... https://www.radheshyamtulsimala.com/where-to-find-original-tulsimala-in-virindaban/