[Tar Elenion]

The main power of all the Rings was to prevent decay or change (what might be termed as a slowing of the apparent passage of time). The Three are specifically said to have been intended for 'making, healing and preserving'. All the Rings could also enhance thae natural powers of a possessor, but there is nothing indicating that the Mirror of Galadriel, the Phial, 'golden leaves', white horses, flooding the the ford, reading minds, or communicating were something caused or allowed by the Three. The Three may well have enhanced the natural ability of their respective possessors to do some of these things, but that was still the ability of the possessor, not the Rings (ie Elrond could already control the river, though may have Vilya made it easier as it were).