Catoptromancy

Meaning: divination by mirror; there is the 'mirror, mirror' technique used in Snow White, and Pausanius gives an account of another, at a temple near Patras:

The sick person let down a mirror, suspended by a thread till its base touched the surface of the water, having first prayed to the goddess and offered incense. Then looking in the mirror, he saw the presage of death or recovery, according as the face appeared fresh and healthy, or of a ghastly aspect. 

Usefulness: 1 (can be used in allusions to Snow White; similarly to metopomancy; or extended figuratively: "Her decisions are made by catoptromancy; she sees her own reflection in everything." "If we only survey our own staff, we run the risk of catoptromancy.")

Logofascination: 2 (that's opt - as in optical, optician etc - in the middle)

In the wild: it gets explored a little further over at World Wide Words.

Degrees: 1

Connections: n/a

Used in: the -mancy chapter: G&P, Book the Third, XXV: How Panurge consulteth with Herr Trippa.

Herr Trippa, going on in his discourse, said, By catoptromancy, likewise held in such account by the Emperor Didius Julianus, that by means thereof he ever and anon foresaw all that which at any time did happen or befall unto him. Thou shalt not need to put on thy spectacles, for in a mirror thou wilt see her as clearly and manifestly nebrundiated and billibodring it, as if I should show it in the fountain of the temple of Minerva near Patras.

The reference to the fountain is explained by Pausanius, above. Nebrundiated and billibodring, whose meaning should be fairly clear from the context, (since Herr Trippa predicts cuckoldry regardless of the -mancy) were invented by Sir Thomas - Rabelais doesn't mention the mirror or what will be seen in it. These will be getting their own posts once I get a grasp on their etymology and figure out exactly how one writes about these things without being prurient, or blacklisted.

Update: nebrundiated and billibroding.