Smoke runes are combination runes. They count as two separate runes: one fire runeand one air rune. Thus, any spell requiring one fire rune, one air rune or both will cost only one smoke rune. The value of 1 smoke rune in Mobilising Armies is 7 Investment Credits.
Runecrafting Smoke runes
At Runecrafting level 15 or higher, they can be crafted in either of two ways: