make strange coin obtainable in seasonal activity, exotic mission, dungeon, and raid example Seasonal activity normal difficulty give 3, expert give 5 Exotic mission normal difficulty give 4, expert give 5 Dungeon give 1-2 each encounter on normal so total 3-6 in expert give 2-3 so total 6-9 Raid give 2-3 each encounter so total 8-10 + additional reward for completing challenge farmable or not i dont know