Mól jelly / goop
A reagent gathered out of the Mól ruins, worked as an accelerant and a catalyst in Mól alchemy
Jelly out of the ruins, and the one piece of Mól alchemy that can be carried in a jar. It is worked as an accelerant and as a catalyst: it does not do the work, it makes the work go, which is why anyone practicing the subject wants a supply and why the supply is a matter of who holds which ruin. The party first heard of it as a reagent bandits were gathering inside the Mól ruin under Haudh-Gwenn (S2E19), and they sold some of it on to Gwenivere Velmont in S2E25.
What it is made of has never been established. Whether the Empire produced it or the ruins go on producing it, and why it should survive seven hundred years underground, were never discovered.