dont wory about it being black thats old school hash oil ,,,iso is polar and pulls allot of chloropyl which wen concentrated turns pretty dark but when spread will leave green streaks,,,, its fine to smoke but wen i do iso (my personal fav for its spreadability ) i usually make keif then fill a baby food jar or mason jar depending what i am working with and then just add enuf iso to cover it and let itsit for a cpl days (less plant in keif so not much worry about it sitting) just shake it ,,, after wards the keif will look like bleached sand on the bottom and the liquid will be jet black,,, i pour into a pyrex and (not recomended or endorsed but my style) light t on fire ,, the fumes of iso burn well above the actual oil which evaps it to its best possible potential end product is jet black and smells beautiful and super potent
DONOT lite iso on fire if ur not ready for all potential problems ,,,, air evap n water bath work just fine just takes alot longer