Lore: Mox
The term "mox" is taken from Magic: the Gathering, and some of the concepts below are similar to... ugh, residuum from D&D 4e (which is almost assuredly stolen from WoW's enchanting profession); while the idea of myrrh trees is lifted from Final Fantasy: Crystal Chronicles. These concepts are combined and modified below to further reflect the nature of Trinity.
Overview
Mox is the physical, crystallized essence of a Force. It is only naturally-occurring in the sense that each of the Forces are naturally-occurring in Trinity; however, it does not manifest naturally in this crystalline form.
In areas of extreme Force saturation - and in other, potentially unknowable circumstances - the very land itself becomes infused with the nature of the Force in question. Plants, being much closer to this infusion than other living things, eventually soak up some of this power and undergo a metamorphosis into a class of tree known as myrrh trees. Each of the nine Forces has its own distinct variety of myrrh tree, and anyone knowledgeable in the Forces can immediately identify the Force alignment of a given myrrh tree.
Myrrh trees have no requirement for light, proper soil, water, or any other sort of nutrition that a typical tree requires. Instead, a myrrh tree feeds directly on the Force that triggered its transformation. In general, areas of high concentrations of a given Force can support no more than one myrrh tree: they are, essentially, competing for the same metaphysical resource, and even if a number of trees undergo the transformation, it takes very little time for one to become dominant, starving the others to support itself. This results in myrrh trees having a rather explosive initial growth spurt, eventually settling into a very slow rate of growth over time.
Myrrh trees have two other properties that are of keen interest to society at large.
The first is that they produce myrrh, a thick sap akin to resin, which - over time - hardens into mox. While less efficient to work with than mox, myrrh serves much the same purpose and can be used in creating items of power related to the Force from which the tree draws its sustenance. A typical myrrh tree produces roughly an ounce of myrrh every few months (with one ounce of myrrh roughly equal to one mox dust pinch, in terms of value). An ounce of myrrh solidifies into a tiny fragment of mox over the course of a year, which has equivalent mass equal to a pinch of mox dust.
The second property of myrrh trees is that, for unknown reasons, they act as a beacon for vilekin. It is unknown if myrrh trees intentionally call out to these creatures somehow, or if they emit some sort of pheromone or possess other plant anatomy that gives rise to this phenomenon. Regardless, as soon as a tree undergoes a transformation into a myrrh tree, vilekin are inevitably drawn to it. Initially, the creatures drawn to the tree are relatively small and easy to dispatch, but as the tree grows in age, the stronger the "signal" becomes.
Some believe that the presence of a myrrh tree doesn't act as a beacon to these creatures, but instead believe that the tree passively creates them: much in the same way that the tree underwent a transformation into a Force-aligned variant of plant-life, the myrrh tree mutates creatures within its domain, turning them into vilekin that the tree uses to protect itself. There are certainly examples of fantastic plant-life in Trinity that behave in this fashion, but they are relatively rare, and such trees have a tendency to possess some level of sentience. Myrrh trees, on the other hand, react to attempts to communication as any other, relatively normal tree, indicating that they have no self-awareness and are acting appropriately for a plant of their kind (though, many admit, when discussing trees that literally feed on the metaphysical essence of Magic, "acting appropriately" may take on new and exciting meanings).
What this second point ultimately means is that, eventually, all attempts at "mox farming" fail, and usually spectacularly, and such regions - while small - become desolate and inhospitable to spoken life. While some would assume that the exoduses caused by these disasters would mean that the saturation of the Force that gave birth to the myrrh tree would fail, this is typically not the case: by the time spoken typically abandon such a location, vilekin are present in sufficient numbers to allow the myrrh tree to continue to grow and feed on the ambient Force saturation. Its continued existence leads to more and more powerful vilekin taking up residence near the tree, which continues the cycle.
There are no recorded incidents of a myrrh tree being discovered in a jagd, though such locations are few and far between.
Like other plant-life, a myrrh tree can be destroyed. This has been done sometimes throughout history as a strategic decision: better to lose out on the potential resources gained from a myrrh tree than to lose the territory to the inevitable encroachment of vilekin. The various portions of a destroyed myrrh tree - its leaves, wood, and other bits - have no particularly interesting intrinsic properties of their own, aside from their absurd rarity.
Mox and Economics
Mox - and by extension, myrrh - is a necessary component in crafting items of significant power. While lesser items can be made through the mere application of a Force, stronger items require the incorporation of a physical manifestation of a Force in order to fuel its powers.
Because of the rarity of mox and the difficulties associated with gathering it, while there exist markets for such items, these typically exist on the individual scale. Nations do not typically participate in any sort of "Force item trade," simply because the rarity of such goods makes it almost impossible for the market to scale up to the point where nations would care about it on a macroeconomic level. Individual cities may export Force items, particularly if they are near a relatively young myrrh tree and have a host of adventurers or mercenaries willing to go forth and extract the resource, but even then, the rate of production of mox is so absurdly slow that any city that claims it is a mass exporter of force items typically lays rest to that claim within a few years, if not sooner.
The mox economy, as it is sometimes referred to, runs primarily not on mox, but on items of power that have already been crafted. The precise value of such an item is proportional to the amount of mox required for its production. While one would think that the value of mox would decrease as the supply is always increasing (albeit very, very slowly), and mox is imbued into items which then retain that value, this is not the case, as items are lost or destroyed on a regular basis, be it by adventurers dying in the middle of nowhere or a creature hoarding items it has found.
As such, the mox economy is relatively stable, and will be for the foreseeable future.
Mox and Sparks
While sparks use mox to produce items of power, imbuing the dust into the component parts of the item to be created and channeling their abilities through it into the item, some items specifically use mox as a focus.
Specifically, a large enough piece of mox can be used in two ways: either as a means to empower the wearer's ability to call upon their Force, or as a deterrent against that Force (accomplished by treating the mox in such a way that it absorbs, then dissipates, incoming energies associated with its Force). These items are typically made into amulets and bracers, respectively.
