2nd formula (spoilers)

[SYED]

in the secret communications, it was said they were still decrypting the second formula from the texts, but an earlier document had the recipe for the earth dragon enhancement oil. So it means to me that the second formula is still unknown. Since it is in the same collection,a nd likely same tome, the two recipes would be connected. I wonder what else might be in those book, both the draconis and the mandarin ones, China was famed for its alchemy, so who knows, imagine if magic can be used to make it fully work.
So an oil that allows dragon properties from the other types to be similarly shared, an oil to remove the enhancement or a oil to grant some kind of human enhancement seems the most likely to be created. It might allow dragons to benefit from the process, if fire dragons gained earth protection, they could once more be able to defend the dragon nation from threats. While they would still be vulnerable to plastic weapons, they might be able to deal with that magically.
Since one formula grants an aspect of an earth dragon, it might grant some other effect. It could bestow the breath weapon of a dragon. The elemental control, since earth dragons can't use magic, other dragons or humans could be able to manipulate earth/stone like water and fire dragons mess with their elements. A permanent link to the earth dragons who provide continual magic, or the ability to emit magical energies like the earth dragons do. It might even allow links to be formed similar to the links created when blood is exposed to a tail spike of a dragon.