Mana is a fibrous plant-like material.
Bluemana is widely cultivated, about 1/5 of a province’s crops are in blue mana. It’s much more expensive than food, but easy to come by. A field of Blue mana takes approximately two annum to grow and requires careful tending and watering (which requires gold mages and/or greenmages). Blue mana cannot be grown in the winter, thus, communities save part of their summer crops for the generation that will live only in winter to use.
Untended bluemana fields will turn black (into black mana) as they wither. Black mana grows wild as well.
Greenmana can be dug from the ground, it is blue mana (not black, it must be buried before it withers) deposited years ago and slowly bleached to a light green color. Green mana is relatively common, however a higher quality of green mana (which can be recognized by its bright green color as opposed to the light green of natural green mana) has been developed by Siam, an old kingdom of Asherati who have aged it by a careful process several hundred years old, which requires goldmages to keep the soil moist.
Redmana grows in only high elevations, the people who farm it there trade it to provinces and Kingdoms for animals and use of goldmages.
Whitemana has not been successfully cultivated, it grows in the sands of the planes and in the desert in small patches randomly to varying degrees of whitness/greyness – pure whitemana is gathered from several fortnights into the deserts by blind-traders (not blind when they start, who go blind as a result of their profession).
Goldmana lines the stomachs of Dragons. That is its only know source. Many children dream of becoming professional dragon hunters – famous examples are a common subject of Bardic legends. Kingdoms typically have a force of 15-20 full-time dragon hunters responsible for providing gold mana for water mages tending fields under protection (and paying taxes) to the kingdom. However, provinces disassociated from the kingdom enough to have their own water mages typically also harvest their own gold mana three or four times each season. Goldmana cannot be stored indefinitely – it dulls and loses its power quickly outside of a dragon’s stomach. Several past kingdoms are known to have tried to capture and breed dragons as opposed to hunting them in the wild – all efforts were catastrophically unsuccessful.