Relics/ dhathu have supernatural powers? I have heard and read that relics of Buddha have certain supernatural powers. I was reading a book once that said that it is not the relic alone that performs these supernatural acts but the deities that protect the relic. Can anyone help me understand this. thanks!
The supernormal acts can happen in 2 ways:


The Person has Jhanic powers and made a strong determination that so and so should happen with the relicts
A deva or being which the power influence matter in the human realm influences the relicts


Generally in my opinion the latter is happens when relicts mysteriously appear in shrine rooms and places of worship. If the relicts do not get veneration in where they are a deva may bring them to another place where they might get the veneration.

The former case may be associated with crystallizing of the relicts. E.g.: http://www.bdcu.org.au/bddronline/bddr12no7/Mun168.htm