The rules says that boosting the number on a base card requires discarding, rather than just evaluating, a number of gems.The gems need to match the color of the base card. This could be different from the card on the map executed, which must be of the same type as the base card, but not necessarily the same color.
I assume the gems still need to match the color of the action?
Also, can you still boost the action itself normally? Which I assume would happen after discarding for boosting base card.The base card is boosted before a map card is chosen to be executed. Any gems not discarded to boost the base card boost the map card as normally.