@turkay1-- I think black cumin is used in some Hindu rituals, although I'm not sure what exactly. I do know that black cumin is called kala jeera in Hindi. It might be offered along with some other things on the prayer tray (pooja tali) during prayers (puja).
I have also heard that black cumin seeds will protect people from the evil eye, sort of like the evil eye beads. You can carry some on you in a little pouch and it will ward from bad energies.