Hmmm - good point. I think that it really could go either way. I think if the concentration of Gerini varied throughout the world, it would probably be more interesting... then Gerini could be sparse in some places, and their could even be no Gerini in other places.
I've really meditated on this concept of the gerini and such. Let me explain what I have already come up with:
Gerini is the heart of magic, or mana. In a regular magical world, magic is used like so: the subject "pulls" mana from the area surrounding him/her, and then casts a spell. Now, on this world, gerini is substituted as the magic's source...it is the only place in which mana is held. -- in other words, it IS magic, but it is also a spirit. In the spirit world the gerini is..... a bit like the way God and the trinity works. Much like how God the Father, the Son and the Holy spirit are all God, yet are still seperate entities; the gerini is based on this idea, however tweaked. Instead, the gerini is a creation of God, in a seperate "ethereal plane" ...the world could be in a different existence all together - I'm not sure how that will work yet. (By the way, when I create games, I always like to put them back to their source -- God.) The gerini is ALSO multiple entities, yet at the same time "the Gerini," one entity... I'm pretty sure I went through a lot of this before-hand, but bear with me.
For Geri-technologie's sake, let me explain how a vehicle would work: the closer the Geri is to the ethereal world, the more translucent it would be. Remember, the manifestation of the Geri in the "real world" is that of a beast.... so, a magic-user that used Gerini, and was low level, would essentially have a fully substantial beast, becuase that would be the furthest away from the ethereal - invisible - form. Some cars, then, that use gerini at a low level would run on a gerini-beast that was semi-translucent... perhaps the beast would be on the hood of the vehicle. And when the vehicle starts up, a roar from the beast could be heard faintly... perhaps even loudly, considering the personality of the beast.
From this I came up with the Jedi-type class. This class would use gerini when it's closest to the ethereal form. In other words, when the subject "casts" a spell, no effect is seen - it simply works. Like that of the Jedi-push... this class would be able to "push" things as well.... along with a lot more other magical powers.
On top of this, since lower level gerini is a fuel for technology, others would be able to get magical properties as well... not nearly as powerful, mind you, but still gerini, or magic. If they equip themselves with genetically altered gerini-eyes, they could see better...perhaps even see in complete darkness, or with night vision or ultraviolet vision.
--- I know this is a lot, so tell me what you guys think.