Fezem, The Fen Szem Cure-All

The Fen Szem Wort has intrigued naturalists for its miraculous properties. Rare and mystical, these plants have a unique ability that are immune to diviners and they cannot be planted elsewhere. This means they cannot be harvested and mass produced for cures. Due to this, the medical potential these plants offer has been a long time coming. Tests usually resulted in total loss and finding more specimens were of course difficult to come by.
However, recently naturalists and doctors in the western Tambux region have found a way to extract the beneficial essence of the plant. The process is long and tedious, but the group has verified it is possible. The results are a small vial no more than an ounce of the essence. The concentration can be diffused into solutions for application as seen fit. It can be added to a drink for inner healing or kneaded into a paste to apply to various wounds. It took a considerable amount of coaxing from the local lord to allow this to happen, but luckily some convincing allowed them to test the original specimen and helped formulate the concentration.
The claim of "Cure-All" is rightly given. The naturalists have touted it to cure all from headaches, to regrowing limbs. Any natural malady can be cured through one dose of Fezem. The naturalists declare it a tragedy it cannot be easily made available, but even kings would need to wait for a chance of cure.
These true cost of the concentration cannot properly be calculated. At this time the naturalists believe it to cost not money nor tasks nor quests, but veritable regions and kingdoms.
It should be noted the divining immunity is still active even in concentrate and applied forms. The person who has Fenzem applied to them is not immune to divining magic.