Black Turmeric Curcuma Caesia AKA Kali Haldi and Nalla Passapu is an endangered variety of Turmeric. It has pale to dark bluish rhizomes. (Photos of Black Turmeric can be seen here.)
It contains 28% Camphor and smells like camphor. There are many rumor about Black Turmeric burning Camphor Pieces when kept in contact is false. There are even many videos claiming such activities, however one should not believe in such misleading information and fall into traps of fake item sellers.