When you play through Age of Alchemy for the first time, you may wonder - "Why can't I find arcana?".

The answer is - it only spawns on existing resources and its presence is indicated by red vfx.

30% chance Arcana spawn for: Cattle, Coal, Coffee, Cotton, Flax, Deer, Gold, Grapes, Iron, Marble, Olives, Rice, Sheep, Sugar, Tea, Tobacco, Wheat

You have to focus and look there, zooming camera.

Good luck if you are color blind, but once you notice it for the first time it gets easier.

It is also missing from the field's tooltip, which imo should be mentioned there.

Hopefully they will fix it in some future patch.