Youtube Link for Black Turmeric : https://www.youtube.com/watch?v=wwjXrPMPoxU&t=5s
Black turmeric is used in kali,Mahalakshmi and Durga puja.It is believed that it brings good fortune,health,wealth and prosperity.So it is kept with Gods and Goddess to worship.It is also kept in cash box and wallet.
*Black Turmeric is also used to remove Black Magic.
*It is also used in Vastu to counter and removes the negative forces in the house.