Certus essence, fluix essence, and silicon essence cannot be crafted into their own respective items of certus/pure certus, fluix/pure fluix, and silicon.

fluix and silicon essences have no crafting recipes associated with it.

Versions:
Minecraft: 1.16.3
Forge: 1.16.3.34.1.1
Cucumber: 1.16.3-4.1.2
Mystical Agriculture: 1.16.3-4.1.0
Mystical Agradditions: 1.16.3-4.1.0
JEI: 1.16.3-7.3.2.36