Wouldn't that be Second Sight? It allows you to "see naturally invisible things such as spirits and the boundaries between regio levels."
I really do think that what the Virtue offers equates to 3 Minor Virtues. I don't see that there is a "leftover Supernatural Virtue." What benefit do you see as not being on par for a Minor Virtue?
You are given a Minor Virtue.
You're provided a bonus to social interactions with beings aligned with your chosen Realm, which is nearly identical to another Minor Virtue.
And I think +1 modifier to aura bonuses to be very useful as not only does it give a +1 bonus to ALL Supernatural Abilities when in a favorable aura, it also adds to Lab Totals and spell casting.
Yeah, Second Sight will help you cross regio boundaries. I was really thinking about Wilderness Sense, as in something that would help you live, find your way, etc, in such an environment. Second Sight doesn't really help with that.
That's what I was referring to. It was just an idea. If you're happy with your Virtue as it stands, that's fine with me. The scope is much more reasonable than what you had before. It's just a bit of a pity that you have to leave one "minor slot" up to the player rather than make up one last thing that will fit it. I'll leave it to other people to figure out if it is underpowered, though I do agree it seems to be missing one last little something to tie everything up together; which doesn't mean one more minor virtue. shrug.
With the added benefit that, unlike "Alluring to X", you don't have to take the Gentle Gift. That's a nice plus.
As Ex Miscellanea is my favourite House ,
guess i was trying to come up with something a bit non-Hermetic.
A Major Virtue can be balanced out by including a Story Flaw , for example ,
or by having a Supernatural Ability associated with it.
For a Magus , an ability is always an XP sink ,
as getting to Rank 10 is about the same as 23 Ranks in an Art.
And the +01 Aura bonus does not seem very useful to a non-Gifted Companion ,
unless they already had a supernatural ability or magic resistance.
If you are happy with it in play , then that is all that really matters after all.
I understand what you're saying better now. I'd hate to step on Wilderness Sense's toes though as most regiones are in some wilderness environment and so would fall under that Supernatural Ability. It would be an interesting Minor Virtue though...
One of the reasons I want to leave the Minor Supernatural Virtue up to the player is that I'm designing this Virtue to be a way to individualize Ex Misc magi. I've really felt that the Virtues available to starting Ex Misc characters to be far too narrow to develop unique traditions of magic. You can't even take Mythic Blood for goodness sake, which is really annoying. It almost made me want to push my troupe to change it to a Major Supernatural Virtue instead of a Major Hermetic Virtue. But, getting back on track, I wanted the player to be able to choose the Supernatural Virtue as a way to individualize the character's connection to the chosen Realm.
Very astute! . Or choosing Inoffensive to (Being) first. I definitely think that this bonus is quite useful and helps bring the Virtue to a level matching other Major Supernatural Virtues. I think the Virtue as a whole intersects with parts of the RAW in interesting ways and provides benefits in a broader arena, rather than focused.
I can see that point of view but really feel it allows a wide range of non-Hermetic types. For example:
An Ex Misc magus based in the Theban Tribunal whose magic tradition derives from early Gnostic Christianity. He takes Affinity Divine Realm. As his free Minor Supernatural Virtue he takes Sense Holiness and Unholiness. Fitting his magical tradition he takes some RoP: tD magic stuff (sorry, don't have the book yet). All these powers/spells/doohickeys gain +1 to any aura bonus and so does his Sense Holiness and Unholiness.
I don't see that benefiting from a Supernatural Ability Virtue is a balancing factor, regardless that it's a skill that must be increased. Supernatural Abilities are non-hermetic (usually) powers.
I think the +1 modifier to aura bonuses is quite useful to Companion characters. Of the 11 Minor Supernatural Virtues in the core, 8 are abilities.
Example:
A young man (Companion) who fell in love with a Faerie prince and was rescued by a covenant. He has Affinity Faerie Realm. As his free Minor Supernatural Virtue he takes Enchanting Music, which increases in potency when in a Faerie or Magic aura. And, any other Faerie powered abilities, such as Entrancement, would benefit.
This is the true test. We'll see how balanced it is when play begins.
It's just a bit of a pity that you have to leave one "minor slot" up to the player rather than make up one last thing that will fit it. I'll leave it to other people to figure out if it is underpowered, though I do agree it seems to be missing one last little something to tie everything up together; which doesn't mean one more minor virtue. 
. Or choosing Inoffensive to (Being) first. I definitely think that this bonus is quite useful and helps bring the Virtue to a level matching other Major Supernatural Virtues. I think the Virtue as a whole intersects with parts of the RAW in interesting ways and provides benefits in a broader arena, rather than focused.