Resonance is a mage term to describe the spiritual affinities of an object or place that manifest as a part of its Aura. A knife used by a husband against his wife in an argument would have a resonance saturated in rage and/or hate, while the beloved doll of a four-year-old would have a resonance of affection. In this regard, Resonance is similar to Essence.
The strength of an object or creature's resonance varies in both a material and a metaphysical sense, depending on an aura's density. Mundane material objects are the densest, having only a faint background resonance and whatever traces they have picked up from contact with other, more intense, auras. The resonance of a place behaves somewhat like the Chinese theory of feng shui; the totality of local influences gives a place a certain "vibe." This vibe exemplifies a theme and/or mood, influencing people's feelings and possibly manner. Regional resonance is determined mainly by the accretion of strong behaviors over time, such as murder or caregiving. The supernal Mana infused into Artifacts gives them a clearer resonance than mundane objects. Living beings have a stronger resonance still, with the auras of the Awakened being much bolder than those of Sleepers (unless disguised in some way). Ephemeral objects have a very clear resonance, with no material element to dampen or conceal their auras. The same is true of ephemeral creatures like spirits. In general, it is much easier to perceive the resonance of an active spirit than that of, say, a mundane piece of rock. Spirits in the Shadow Realm are attracted to resonance whose qualities are similar to their own natures. They tend to cluster on the other side of the Gauntlet from such places, influencing them with spirit powers.
Mages can use Resonance in order to form connections for the Space Arcanum to cast sympathetic spells. In addition, it can be a great asset to be informed of the general Resonance of one's surroundings, in order to use them to more effective ends.